Ignition shorted to the Headlamp Switch?

[BrandonMc]

Hi,


I've had the greatest opportunity to go through the entire dash and make sense of the wiring. This was a rats nest, eliminated a positive to ground, eliminated 20' of electrical wiring that was unnecessary. I found a lot wrong. Actually, after making sense of it, the dash controls for the batteries and dual, mom, etc.. they all work now and alleviated so much of the confusion that was preventing me from understanding this electrical system. Before getting into this further, and seeking out the regular issues like making sure the connections are electrically taped, sealed, secured and sorted from start to finish------ does anyone have any insight as to where to look to isolate an electrical issue..


Question:
I must pull my headlamp switch on and that is when the RV will start. The RV will not start unless the headlamp switch is pulled and that will ground out whatever needs to happen to have the brake light, etc and ignition work to start the vehicle and successfully drive it. For example, the RV will shut down if I shut the headlamp off.

I kinda straightened out some wires by feeling behind the dash and all that, and the engine runs after turning the lights off instead of killing the engine at this point (perhaps because of this). I also heard the windshield wiper module buzz, like a crazy oscillation coming from the module.


thanks

[stanDman111]

boy is that ever a strange one ?

[BrandonMc]

boy is that ever a strange one ?

no kidding!! and morale killing a little bit too, its simply got to be a wire shorting out somewhere, but perhaps the switch itself could be a culprit too?


If it helps a diagnosis - the last couple times it ran before performing this stunt was I was experiencing some audible dips in voltage per the speed of the aux heater in the rear, and the meter up forward in the dash was reading low, close to between 8 and 10 volts dipping up and down. Because of this, I swapped for a new reman alternator. The battery is 2 months old as well, and these source points can be eliminated. I was reading a steady normal voltage on the meter on the way back after a alternator swap.


I'll let you all know how it goes under the dash again tracing down connections at the most suspect locations... which likely will happen in the next few days. 

[Froggy1936]

Since it is now advised to have headlamps on at all times when driveing And The condition would slow down a thief Just leave it like it is  W%  Frank

[stanDman111]

not a bad theft deterrent  idea, but he definitely  has something wrong , could lead to a melt down or even worse a fire  & we don't want to have any of that

[M & J]

TJ has first hand experience with that....

[stanDman111]

yes and it was a darn shame

[BrandonMc]

ok, I have good news today and I'll share it! 

By happenstance, I was turning the key in the ignition, and only every other time did the brake light, the choke and check engine light come on pre-ignition like normal. This is the issue where after the headlamp switch was pulled, I could get those to all turn on and start the vehicle. I believe the problem is with the ignition switch with the key to the vehicle itself. I could wiggle the key and turn off and on and get these systems to light.


the news about the electrical if anyone could ever find this useful....
I had it die while driving it back to the parking spot today, I happened to be at the same roundabout where I've previously had it die!!! Because of turning and shorting and disconnecting the systems electrically.  Only that other time, it was because the battery connector lug broke in half! I had it vice-locked, and back on the road in 5 minutes. So this time, I happened to be able to once again barely coast the RV to a stop where traffic can pass me by quite easily. I just place it in park, and pop the lights on again. It starts right up, and we're on our way again. I notice though, the voltage meter is running low close to 8-10volts, and the turn signal each time it blinks will draw the voltage down past red at 8volts!!! Anyways, I park it at my spot thank god, and that's when I take this headlamp switch and ignition switch out and kinda figure this ignition switch is really the cuplrit.

[DaveVA78Chieftain]

I've had the greatest opportunity to go through the entire dash and make sense of the wiring. This was a rats nest, eliminated a positive to ground, eliminated 20' of electrical wiring that was unnecessary. I found a lot wrong.

My perspective is that you have crossed some wiring as part of that evolution.  My feedback is based on the 1988 P30 wiring diagram.
For one, the ignition switch and the headlight switch are two completely separate circuits.  Two separate power sources that only merge at the starter solenoid.  The do not cross connect. The Alternator, Headlight, and Ignition switch fusible links all merge at that point.
Note:
Pin numbers and first number of wire designation on GM drawings represent circuit numbers.  That is how you follow information on the diagram.
0.8mm = 18 gauge
1.0mm = 16 gauge
2.0mm = 14 gauge
3.0mm = 12 gauge
5.0mm = 10 gauge

There are two pin 2 circuits in the main bulkhead connector. 
1) Ignition switch HOT
    A) Outside: 12 Gauge red wire from bulkhead connector that goes to Magnetic Starter Relay (on bracket above alternator).  2nd wire from that magnetic solenoid post that goes down to a starter solenoid fusible link.
    B) Inside: 12 gauge Red wire from bulkhead connector to pin 2 of ignition switch.
2) Ignition SW Start
    A) Outside:
        1] 10 gauge purple wire from Magnetic Solenoid to "S" terminal on starter solenoid.  Also a 2nd wire of that Magnetic Solenoid post goes to the fuel pump relay for start override.
        2] 12 gauge purple wire from "coil" side of Magnetic Solenoid to pin 906 on bulkhead connector
    B) Inside:
        1] 12 gauge Purple wire from bulkhead 906 to Neutral Safety Switch
        2] 12 gauge Purple wire from Neutral Safety Switch to pin 5 on Ignition switch
3) Ignition Sw Power to distributor
    A) Outside: 12 gauge Pink wire from distributor to Pin 3 on bulkhead connector.  A 2nd wire of Pin 3 also goes to the Fuel Pump Relay.
    B) Inside: 12 gauge Pink wire offPin 3 on bulkhead connector to pin 3 on Ignition Switch.  A 2nd 12 gauge Pink wire off Pin 3 on bulkhead connector goes to Chevy Fuse box as supply for IGN, Gauges, and Turn Sig fuses.
4) Headlight Switch HOT
   A) Outside: 12 gauge Red wire from Starter solenoid fusible link to bulkhead connector 2nd pin 2.
   B) Inside:
       1] 12 gauge Red wire to pin 2 on headlight switch
       2] Another 12 gauge Red wire that goes down to the chevy fuse panel for supply to the Horn, Tl lamps, and Hazard Lt fuses.

You have not indicated if the starter will engage with the headlight switch OFF (starter turns but engine will not start)?  Trying to establish if power is getting to pin 2 on the starter switch

Again, I feel you have a miswire from your original work.

[DRMousseau]

This was a rats nest, eliminated a positive to ground, eliminated 20' of electrical wiring that was unnecessary. I found a lot wrong. Actually, after making sense of it, the dash controls for the batteries and dual, mom, etc.. they all work now and alleviated so much of the confusion that was preventing me from understanding this electrical system

I might agree with Dave, in that you jus might have something twisted in your efforts. BUT,... it might jus be that something UNSEEN may actually be twisting YOUR efforts in some way and causing some great confusion! Hm?


You noted quite a mess under there, and who knows HOW or jus WHAT someone may have done. My guess, is they probably created a lot of excitement and probably a few big sparks here and there too! Whoops!


You seem to suspect the ignition switch,... and you'll likely find it needs replacing anyways, being loose and squirrely and all. Maybe jus worn, but MAYBE some sever internal damage too, due to previous careless efforts of the nest builder! lol! If your replacing it,... then tear it apart to see for yourself jus WHY it may be failing and if it actually IS the source of trouble for some reason unseen. Any internal sever damage like badly burned contacts, insulation or connection points, might lead you to more closely inspect that particular circuit.


"I was jus tryin' to hook up my new radio, and I think I blew something,... now it don't work at all! Any idea what happened???"
Yup,..... YOU happened!!! D:oH! UGH!!!!


SOOOOO,.... I'd wonder of OTHER unseen damage! Doesn't take much to internally ruin a relay, switch contacts, and even a solenoid (though very rare)!!! Check those relays in these systems AND behind the blocks in which they are plugged into. A brief moment of carelessness by someone can easily cause an unseen short or other damage in these areas that can drive ya insane!!!


That's quit a voltage drop that would cause me some HUGE concerns!!!!

[TerryH]

You seem to suspect the ignition switch,... and you'll likely find it needs replacing anyways, being loose and squirrely and all. Maybe jus worn, but MAYBE some sever internal damage too,

Check those relays in these systems AND behind the blocks in which they are plugged into. A brief moment of carelessness by someone can easily cause an unseen short or other damage in these areas that can drive ya insane!!!

That's quit a voltage drop that would cause me some HUGE concerns!!!!

I have to agree. If you are going to the effort and trouble of removing the ignition switch and are having trouble with it - fiddling, etc.- replace it. It won't repair itself and can easily result in a tow requirement.
Voltage drop is scary.

[BrandonMc]

Thanks for the help here dave! yeah, i wouldnt doubt something is connected wrong at my hands. I havent yet got into the wiring jackets from either one of those switches, And they seem intact. I saw the solenoid youre talking about too. Also as suggested, there may be a relay thats giving hassle, Just like the ignition switch cyliner was loose and being worked on, One of the relays up in the center dash area had been taped to make sure it stays put, And i removed this tape.

[DaveVA78Chieftain]

OK, I gotta ask a question then, you have downloaded the free to members 1988 P30 P30 Manuals from the member area right?  They sure make life a lot easier.

Section E of Wiring Book is for the P Series Motorhome Chassis
Power Distro: pdf page 337 (Section E Page 3)
Headlights: pdf page 344 (Section E Page 10)
Start/Ignition: pdf page 351 (Section E Page 17)

While the 1987 version is also there, it is a bit difficult to use.

[DRMousseau]

I'm one of those that has to know "WHY" all the time. Must have drove my grandpa crazy, and fortunately my dad was very patient,... never really giving a direct answer, he often jus sorta "directed" me, to discover for myself and answer my "whys" much on my own.


Jus repairing or replacing something doesn't ALWAYS fix the problem. Without knowing "why", I'm jus not certain that I actually fixed it.  Hm? And neither was dad! LoL!


I really hate to damage wire and component jackets and relays that MAY not actually be faulty, jus to verify some suspicion. Good diagrams, schematics, AND the tools, skills and knowledge necessary to use them are usually gonna save money and time, while often answering that "WHY"!
I REALLY hate replacing one part after another, only to eventually find a simple why that didn't even require parts!!!  D:oH! ACK!!!!


Unlike most schematics, a lot of diagrams jus show components only, with no actual or usable info of internal workings, circuits, contacts or anything more than connection ends and a pic or drawing. A GOOD schematic is going to help you trace and test that switch (or relay) without damage to jackets and covers!!! AND, you should also have access to each wire as a disconnected individual component itself, allowing you to test for continuity, resistance (corrosion), and shorts to ground or even to nearby "component" wires and circuits.


I've found what appears to be a good relay outside, only to be a solid block of corrosion inside. And more than a few solid clicking and functioning solenoids that have no contacts inside at all. Totally melted away!!! And those pesky, crumbling "green" copper wires hidden in the insulatin' jackets, often pass voltage,... but no current!


So make SURE your "suspect" parts are actually faulty, and that the true "guilt" isn't still hidden nearby or somewhere else. As Dave noted, the ignition circuits and others are typically isolated and SHOULD be rather independent from one another. Look closely to areas and components where these MAY have accidentally converged. One famous and notable spot, is BEHIND the fuse and relay block,.... where some folks "carelessly" tap for their latest added "auxiliary lights" and "cool CB"!!! And watch for those spots where they may have "slipped", causing a damaging arc. W%

[BrandonMc]

OK, I gotta ask a question then, you have downloaded the free to members 1988 P30 P30 Manuals from the member area right?  They sure make life a lot easier.

Section E of Wiring Book is for the P Series Motorhome Chassis
Power Distro: pdf page 337 (Section E Page 3)
Headlights: pdf page 344 (Section E Page 10)
Start/Ignition: pdf page 351 (Section E Page 17)

While the 1987 version is also there, it is a bit difficult to use.

thankyou for this information! I'm a member, but for some reason, never previously downloaded this particular electrical manual. I'll be up tonight studying this, and going back out and back at it tomorrow! Was out there today tracing out wires precariously through the dash without a good diagram.

Perhaps I need to look into these fusible links, It could definitely be these, never worked with them. Could explain the shorting-like activity in the electrical system as I take a sharp turn, as I've not noticed anything too particularly loose. I also found it wasn't the wiper control that was making the buzzin/oscilating noise, but a 5 pin relay making this issue, I wish I took this relay out because I don't have it to reference at the moment, although it was located between the governor box and the wiper control box in the center dash interior. It may be a horn relay, because I remember the numbers looked like this. Its likely a weird culprit of some sort, I remember the horn faintly beeping while turning the key a little while back but it hasn't happened lately.

In a related search, it appears forum member Engineer Bill is going through a lot of the same things described here. Going to be a good evenings worth of reading about all this....

[DaveVA78Chieftain]

The relay could also be for the fuel gauge for switching back and forth between tank sensors for input to gauge

[BrandonMc]

I went back out and attacked the electrical issue once again. And it hit me like a ton of bricks... While removing the stock stereo last year, I tucked away some wires thinking they were only meant for the stereo. Of course these wires have been out andnot totally exposed, but taped off while I scratch my monkey brain wondering what has happened. I realized, that with the way the dash is wired is with many tap offs and tie ins to the main wire, so you must follow back a lot of wire to find where it all goes. These wires were left unconnected.


You ever have one of those days where something just clicks in your head and you just know at that point what was wrong? Well I connected the negatives to ground, and the positives to their respective BATT or IGN. Basically, I started it right up, and the alternator under the electrical panel was performing as it should as I watched it top the battery off and then back off the voltage. The headlamp switch wasn't shutting the engine off either, or preventing it from starting. Didn't drive it in the 40-80mph gusts of wind today, however, I have some really positive expectations this is all solved.


Still doesn't explain why a positive was connected to ground initially, but now I believe it's all steam ahead! My spring break 1000mi trip can actually happen now! 

[M & J]

 

[DRMousseau]

GREAT!!!!
I jus knew you'd find it!!!!

I couldn't begin to count the number of vehicles of ALL kinds that have suffered at the hands of DIY's, well meaning others, and even "mechanics" and "technicians" who really have no knowledge of even basic electricity and a no real idea in the proper installation of radios, tape decks, CD players, amps, CBs, aux lights and horns and so many other items. Many are then crudely removed before sale of vehicle or item, and make matters left behind so much worse.

[BrandonMc]

GREAT!!!!
I jus knew you'd find it!!!!

I couldn't begin to count the number of vehicles of ALL kinds that have suffered at the hands of DIY's, well meaning others, and even "mechanics" and "technicians" who really have no knowledge of even basic electricity and a no real idea in the proper installation of radios, tape decks, CD players, amps, CBs, aux lights and horns and so many other items. Many are then crudely removed before sale of vehicle or item, and make matters left behind so much worse.

No kidding. We all save thousands of dollars doing it ourselves... and eventually get it done right too without someone half-assing it......even if breaking things as we learn as we go!!


Thanks for your input everyone!