Headlights still flashing on high beams!

[ClydesdaleKevin]

So I cleaned up every ground I could find.  Bought a new headlight switch in case the one I bought a while ago was defective.  Remade every connection done by the PO that I didn't personally make to make sure they were done right.  Even removed, cleaned, and reinstalled the battery ground cable!  Even ran two new ground wires, one from the switch body itself to chassis ground, and another heavy ground wire from the cluster of grounds on the back of the speedo, right to the chassis.  I used dielectric grease on every connection.  I removed the headlight plugs from the headlights, checked them, and reinstalled them with dielectric grease.  I couldn't find any other ground connections. 

Signals work just fine.  Marker lights work just fine.  Low beams work just fine.  Its the high beams that flash.

I started the engine after working on the electrical system all day long.  Let it warm up, and while it warming up, I turned on the signals.  Perfect, with no needle bob on the volt meter anymore, and no drop in voltage.  Turned on the marker lights.  No drop in voltage.  Turned on the low beams.  No drop in voltage.  Turned on the high beams.  No drop in voltage.

Then I left the high beams on...and about 10 minutes later, they started flashing erratically again!

Back to low beams, and they were steady...

What the heck could the problem be?

Okay, maybe someone could help me with a polarity question for when I attack this again tomorrow.  On the the back of the high beam lamp there are two plugs.  If I'm looking at the plug after unplugging it, anyone know which is supposed to be positive, and which negative?  The plug holes go like this when looking at them from the front:  l  l

Okay, how about the low beam?  Which two are supposed to be positive, and which are supposed to be negative?  They look like this when looking at the plug:   l _ l

I'm going to try to trace the wiring from the switch to the wiring on the headlights if possible...and again, from the plugs back to the switch. 

There was a significant difference between the driver's side voltage at the plug, and the passenger side.  Driver's side was 12.5 on the volt meter, passenger side was 10.1 volts. 

I'm at a loss here.  I'm trying, but whatever connection is loose, be it a ground or a positive connection, it isn't any of the ones I've found so far!

Any more help or suggestions would be greatly appreciated!

Kev

[Wantawinnie]

When you mentioned putting in a new headlight switch does that include the dimmer switch? I've had two of those fail and flash the high beams on and off.

[ClydesdaleKevin]

Instrument dimmer is built into the headlight switch.  There is a separate dimmer switch that controls the REST of the dash indicator lights, but its on a separate circuit.

Kev

[HandyDan]

The dimmer switch was going to be my suggestion.  Do you have the switch on the floor?  It could have a problem. 

[jkilbert]

Kevin,
I'm thinking dimmer switch like HandyDan .


John

[ClydesdaleKevin]

Okay.  The dimmer switch for the main dash board is built into the headlight pull switch.  It controls how bright the gauge lights are.  There is a separate dimmer switch to the left if it, which controls how bright the other little lights are on the dash board.

Unless you guys are talking about the headlight high beam switch? 

On ours, its not on the floor, although I do miss having a floor foot switch.  Its built into the signal light switch on the column.  You pull it towards you to turn the high beams on and off. 

Wiring looks okay going to and from the column, with no breaks or visible shorts.  Is this what you guys are talking about?

Sure hope its not in THAT switch!  I really don't want to have to take the steering wheel and column apart!

Kev

[Wantawinnie]

Kev,

That Hi Low dimmer is the switch we are referring to. Two of those type have failed on me that were mounted on the steering column incorporated with the turn signal lever. One of the foot type is going in my dad's truck right now too. 

[DonD]

Kev, is the blinking of the high beams rapid or slow.

[ClydesdaleKevin]

Sort of erratic, Don.  When it first started it was blinking consistently off and on at a steady time.  And it would happen almost right away.

Now, it take about 10 minutes for it to start flashing, at least in the driveway, and now its more of an inconsistent flickering...flash flash...flash flash flash...flash...flash flash...both fast and slow.

I decided to do nothing today, although I did pick up the parts for installing the freshwater tank, which I'll do tomorrow.

Going out shopping with my sis and Patti today, but tomorrow I want to check the voltage at the headlight assembly plugs and make sure the ground wire isn't carrying any current to ground.  At least that would help to rule out a short.

Getting the dimmer switch out of the column doesn't look easy!  Looks like I'd have to pull the horn button, pull the steering wheel, and then I would imagine I'd have access to it.  Its seems like it would be a lot easier to find out which wire going to and coming from the column is the high beam power lead, and just install a floor switch!

Hmmmmm...That's not a bad idea...lol!

Especially since my headlight dimmer/signal switch also has the cruise control and wiper delay integral to the arm as well.

Kev

[DanD2Soon]

Hey Kev.
Just my 2 cents worth...  I didn't think ANY headlights run on direct power from their switch anymore - yes on the old floor dimmers but not now - check your wiring diagram.  I'm guessing you're gonna find two separate relays; probably plug ins; one low beam; one high beam.  The selector switch handles the relays but the relays handle the real amperage to the lamps.  I'd be looking for a faulty or loose relay.  You may even be able to hear it - buzzing, clicking or arcing in time with the flashing...
Good luck as always - DanD

[ClydesdaleKevin]

Thanks Dan!  I only found one relay so far.   Well, one headlamp relay.  The round one in the fuse panel is for the signals, already replaced with an electronic unit, and the other square relay near the fuse panel is for the horn.  The headlamp relay is right under the fuse panel and has just been replaced.  There are no other relays near the fuse panel, or anywhere under the dash that I have found.  There IS a largish relay in the front compartment where the radiator lives, but I'm not sure what its for.  Its on the driver side.  Maybe I'll listen at it when the headlamps start flashing!  I'll also stick my head under the dash when they start flashing to see if I hear any clicking or arching or whatnot...maybe I missed a relay!  Could be hidden anywhere really.  Thanks for the tip!

I hate driving at night, so worst case scenario is that we'll only drive during the day, and if it goes into evening, only use the low beams.  I'm trying to find it, but so far its kicking my but!  At least we sorted out the signal problems and the volt meter bobbing!

Kev

[DaveVA78Chieftain]

Kevin,
Far as I can tell, GM did not use a headlight relay in 84 through 90.  The best reference info I can provide is a scan from  1990 book.  In 1990, GM did not produce a quad headlight setup for the P30 chassis model but did for the P30 truck version.  I am providing the pdf data for both.

1990 P30 fwd control chassis: http://www.mediafire.com/view/?g4iug0o9vu66yio

1990 P30 truck chassis (quad headlight): http://www.mediafire.com/view/?880lda2g7iomhi7

The quad version also reflects the use of the headlight switch on the column.  I doubt 88/89 was any different from these.  If neither of these are correct, then HR modified your install and your sort of on your own.

Dave

[ClydesdaleKevin]

Thanks Dave!  I'll try to download the links in the morning.  The bandwidth here sucks, and I can barely even get a page to load at certain times of the day.

Kev

[ClydesdaleKevin]

Okay, some new developments.

I spent all day working on the RV on this fine rainy day, so I found some things out...once I finished fixing the leaks under the bathroom sink with Flair-It fittings.

First I had to go to an auto parts store...Advanced Automotive was the closest...for a harmonic pulley puller.  I used to have one, but it disappeared out of my toolbox, so I had to buy one to pull the steering wheel.  Worked like a charm.

So the steering wheel was pulled and I had access now to the signal light switch.  Turns out the dimmer is NOT built into the signal light switch, but rather its in the signal lever itself, which is a multi-function switch that operates the cruise control, the intermittent wipers, and the high/low beams.

Since the signals work fine now, I left that switch in place, and removed the lever, held on by one screw, and unplugged all the connections the wiring harness goes to.  One grey wire terminates at a plug, several multicolored wires go to another plug, a few more go to the wiper control box, and then one...just one...tiny orange wire goes to the headlight relay.  Yep, its definitely a headlight relay!

Once I had the lever removed from the column, I noticed it has a back cover held on with one tiny screw.  I removed the cover to reveal the wiring. 

The plastic body of switches is held to the metal lever with a pivoting pin and is spring loaded.  When you pull it towards you, it pushes in the high beam switch...pull it towards you again, and the little plunger on the tiny switch pops out.  Seemed to function well with no burned appearance or odor.

The orange wire goes from the relay, all the way up to the tiny little dimmer switch.  The other wire going to the dimmer switch is a common hot wire coming from the unused cruise control switch.

Hmmmmm....

Coincidently the cruise control stopped working right about the same time the high beams started acting crazy last year. 

Methinks I may be on to something!

I took the whole assembly down to the Advanced Auto, who couldn't cross reference the exact switch and wiring harness with anything else.

So they called a place in Baton Rouge, B&B Automotive Warehouse.  They said if they can't find and get the part, no one could.  The B&B folks actually found the factory P30 multi-switch, said it was a factory part, and IF the factory still had it, it would be around 140 bucks.  By the time I got home they had already called back and said the switch is unavailable.  Ah well!

So now what to do?

I have a sneaking suspicion that the problem might actually be in the cruise control circuit, and not the dimmer switch.  Again, they both stopped working at about the same time.  Power is still obviously getting to the cruise control switch, and then to the dimmer switch, so I'm thinking of trying an experiment.  I think I'll run a new hot wire up into the switch lever housing, and isolate the dimmer switch from the cruise control circuit.  And see if that works and clears up the problem.

If it does, problem solved!  I never used or liked the cruise control on this RV anyways, so it would be a done deal.

If it doesn't work, then the switch itself is again the number one suspect.

That means a new relocated switch, since the one on the column is not replaceable, and also controls the signals and wiper delay module.

So I think at that point I would have 2 choices.  Either a foot switch, just wired as a switch to energize the hot orange wire to the headlight relay, or a toggle switch on the dash, wired to do the same.  I like the foot switch idea better.  Overkill since they weren't used with relays, but it will do the same thing...send power to the orange lead, which would then go to the relay, and then to the headlamps.

And it would be way faster and way more intuitive for turning the high beams off and on than a remote switch on the dashboard.

My only concern is about which wire goes to the high beam indicator light.  I tried tracing it and got lost in a maze of wires that disappear into odd places.  If the wire comes from the relay, its all good, since the relay would energize the bulb in the high beam indicator.  If it comes from the dimmer switch though, that means I have to figure out which wire in the harness goes to that switch.  I'm pretty sure it comes from the relay though...there is only one wire coming from the dimmer switch in the signal lever,  the tiny orange one that goes to the relay.  One power wire coming in, that goes to the cruise control first, and then the dimmer, and one wire out, going to the relay.  I think the indicator light must be controlled by the relay.

If all of THESE efforts fail, I'm at a dead end!

I looked at the wiring diagrams Dave sent me the links to, and downloaded them...and I'm pretty darn sure I didn't miss anything when checking and cleaning up the grounds and connectors.  Everything else is brand new, including many connections.  Everything else is out of the equation except the dimmer switch itself, or a malfunction in the common hot wire that is shared by the dimmer and the cruise control.

I want to try the isolation experiment first.

Kev

[rustyescott1]

Kevin the colum in your mh should be the same one as in the 1/2 ton on up gm vans. check out if this switch has same part #. may be a way to find a replacement. or pull one out of junk yard to see if it is the same. Rusty

[ClydesdaleKevin]

Thanks Rusty.  I went to Napa online and looked at every single multi function switch that they carry, for all vehicles, and not one of them were even close.  Not a single one was the kind mounted with a screw, but were rather...all of them...the push in kind.  Also, not a single one of them looked like they pivot for high beams.

Gonna try running a new hot wire today and get the cruise control out of the equation.  If that doesn't work, then when we get to San Antonio I'll try installing a floor switch running to that hot wire lead on the relay.  If that doesn't work, I'm totally at a loss for what to do about the headlight malfunction, since that is the last piece of the puzzle!

Kev

[rustyescott1]

Kevin email me pics of ur colum and switch. rustyescott@yahoo.com. that should be a standard part , not cost effective for gm to run a specil run of parts for a low seller.  rusty

[rustyescott1]

after 1981 gm went to high beam on the colum an all of it's product line

[rustyescott1]

Kevin ineed a phone # for you , or you can call me 817 301 4962. i've got a lead on your highbeam switch. rusty

[HandyDan]

Kevin, does your switch look anything like this?  I found this at:
http://www.am-autoparts.com/1989/Chevy/Van-P-Series-Forward-Control/turn-signal-lever/AM-11951428/273359.html


Edit:  After further looking into the matter, this isn't what you need after all.  Well, I tried. 

[ClydesdaleKevin]

Welp, I eliminated the switch completely out of the equation.

And it didn't fix the problem...grrrrr!!!

Dangit!



Okay, now I feel a little better...lol!

Alright, so this is what I did on the headlight electricals today.

First I ran a new hot wire from an unused lamp circuit on the fuse panel that is only live when the headlights are on.  Ran it right up into the signal lever switch housing.  To do that I had to remove all of the electrical tape from the wiring going to the switch, and then I of course inspected every last millimeter of every wire for breaks or shorts.  Once connected to the blue wire that came from the cruise control switch (the other end of which I terminated with a small piece of heat shrink to insulate the wire), I rewrapped the cable run tightly with new electrical tape, all the way down to where they plug in under the dash.

Then I plugged in all the connections, used a butt splice to tie the orange wire back into the relay plug, since I had to cut it to remove it, and then it was time to turn the chassis power on and test it.

I started the engine, and turned on the headlights.  Then hit the lever switch to turn the high beams on.  The high beam indicator did indeed light up on the the dash, so at first all seemed well.

At first.

About 3 minutes later, both the high beams and low beams started flashing again...wtHeck!

Turned it to low beams, and they stayed lit, steady and true with no voltage drop.

Okay, now what?

Hmmmmm...

I figured it had to be the dimmer switch itself then.  No other explanation, right?  Since everything else is new and fresh and clean?

I dig into my electrical toolbox and bypass the lever switch altogether down near the relay itself.  I put a female spade connector on the orange wire going to the relay, and another female spade connector on the hot wire coming from the fuse panel and plug them to the spades on the back of a working toggle switch out of my electrical toolbox. 

I start the motor again, and turn on the headlights.  I hit the switch, and the high beams came on, as did the high beam indicator...so I now know that the indicator is indeed controlled by the relay.  Good to know if I was going to put in a foot switch.

Dagnabit!

3 minutes later, the headlights started flashing off and on again!



Okay, now I was getting frustrated!  I listened in at the relays while the engine was running with the lights flashing.  No clicking or arcing sound at any of the relays.  Geesh!  No arcing or clicking sound anywhere at all!  Just the erratic off and on flashing of the headlight bulbs!

Low beams still working fine.

I turned off the engine and chassis power, and reconnected the wiring back to the signal lever switch, since we eliminated it from the equation.  Not going to bother with the cruise control, since I hate it anyways.

Tried the headlights one last time on high, and 3 minutes later,  they started flashing erratically again, off and on.  By the way, the volt meter doesn't even bob when they do this, there are no sounds or clicking, and even though the headlights are flashing off and on, the marker lights stay bright and even.

I even listened in at the mystery relay in the front compartment near the radiator...no sounds.  So after stopping the engine again and turning off chassis power, I unscrewed it from its mounting location, disconnected the wiring harness, and looked closely at the switch.  Old dielectric grease on the five pin connector, and taking the removable top off showed some signs of heat corrosion to the tiny circuit board, but it was warm (not hot) so I assume it was working.  A tiny little sticker on the side of it said "relay, fuel pump". 

Just to be sure, I re-energized the chassis and started the motor, and turned on the headlights and high beams.  They lit up!  And 3 minutes later started flashing again.

Funny thing is, I'm not sure WHAT this relay does.  It says fuel pump on the sticker, but I went back to the gas tank and could hear the in tank pump happily humming away even with the relay removed.  Hmmmmmmm...

So anyhow, it looked a little crusty and I was at the end of my rope, so off to all the auto parts stores in town to find another.  Not a one could get one before Monday, so I just put it back in.  At least I have the part number of it fails later and effects the functioning of the fuel pump.

I'm at the end of my rope here!  I eliminated EVERYthing from the equation, and its still not fixed.

I'm either missing a bad ground somewhere, but I removed, cleaned and reinstalled every single one I could find, or else maybe there is a bad plug end, like at the headlight switch or at the relay?

I don't think its a short, since it takes around 3 minutes to start flashing.  Gotta be a bad ground!

But where?

Another thought I had is that the plug end going into the relay has a tiny resistor, or it could be a diode, jumping two of the connectors.  Can a resistor or diode go bad, and possibly cause my problem?

There are no other elements that haven't been addressed.  Its got to be something super simple and obvious, but I'm not seeing it!

I reinstalled the steering wheel and horn button, zip tied all the wires up nice and neat, put away all my tools, and called it a day.

Not fixed yet though, dangit!

What else could it be?

Kev

[ClydesdaleKevin]

Another question...can a fuse get old and crusty, but not blow, and cause an overheating of a circuit?  I'm stabbing at clouds here...not sure what else to do at this point.

Kev

[moonlitcoyote]

If it were me, and I'm not that good at troubleshooting but...

If the switch is getting power and the power does not fluctuate when the lights are going on and off then I would check the bulbs. I know it cant be that simple but I cant think of anything that would cause the lights to go on and off if the power is steady to the switch. Maybe once the bulbs heat up something is going on in them??


MJ

[DaveVA78Chieftain]

From what I have seen, the only GM application that used any type of headlight relay is one that has Daytime running lights (DRL) installed (Canadian Chassis).  If you have those then there are several more parts in the equation.  There would a 10 Amp fuse marked DRL between the fuel pump fuse and the turn signal flasher on the main GM fuse panel.  I can scan/post the wiring for a DRL system if need be.

If, you do not have Daytime Running Lights installed, then this is a Coach Mfg version.  Power to the headlight relay for the lights themselves would come from a seperate source.  Many Coach Mfg's used auto resetable CB's to supply power to the circuits they added.  They typically installed these type of breakers in the battery space.  Turn highbeam lights ON then see if you can hear some lite clicking noise in the battery area when they starrt flashing.

Dave   

[ClydesdaleKevin]

Thanks Dave!  Gotta be something simple, since I already eliminated the complicated. 

No daytime running lights on this rig though, so its a HRC modification, which of course is boobs up and you can get no good info about.

Thank Coyote...but the bulbs are all brand new LEDs in most of the circuit, and the headlight bulbs are new as of a year ago.

Kev