Heater fan power, dash wiring, round 2

[pinballlarry1]

Sent: 02/11/2007 8:22 PM

I thought I was done working on the dash wiring in the 77 Itasca, but no, it turns out the heater/defroster fans didn't work anymore.  I know they worked recently.  The twin fans themselves by the passenger's knees were ok, so I had to rip everything apart once again to troubleshoot the power source.

Should have removed the steering wheel for better access, but the puller was not on hand this time.  Started with the fan control switch which was kind of stiff and klunky when moved.  I removed it and carefully took it apart.

4 rear spade terminals = 12 volt in, low, medium, and high speed to fan motors.

Cleaned up the round stationary and spring loaded flat sliding contact. Put a small dab of grease on the metal ridges, reassembled it and now it slides smoothly.
I began tracing back the 12 volt power wire and expected it tie into the fuse block backside on the ignition accessory wiring.  However, the power wire passed by the fuse block and landed on this power relay tucked up in the corner. I had seen this relay before, but ASSUMED it was controlled by the infamous BLINK switch to turn off the running lights. WRONG MAYNARD

Further wire tracing revealed that this relay turns on house battery power to the heater/defroster fan switch when the ignition switch in on.
Left pinkish wire comes from the circuit breakers down by the batteries, right gray power wire goes to the fan switch. Center control brown wire comes from the ignition accessory terminal on the fuse block.  Testing showed that while the solenoid would click on, the power could not get thru. A pretty common relay, I had a spare that would work. Mine was a two wire coil, just had to ground one side.

Total pain in the a$$ to get it mounted, lots of cussing. Put everything back together, total time 4 hours. Now the heater fans blow at 3 different speeds, high is really a blast. There was lots of crud and lint on the heater core which I cleaned out.
I assume Winnebago built it this way to keep the ignition switch from carrying the full current load of the fans.  The two fans probably draw several amps more than a standard vehicle. Since the fans are powered by the house batteries, it's a good idea to actuate the dual battery switch when they are running, the alternator power gives them a good boost.
pinballlarry in San Diego


 
From: AlbuqHenry
Sent: 21/03/2008 8:39 AM

Kev, my guess is that someone has a wire or two confused under there...Our 77 brave dash looks just like the one pictured with the fan relay the same and all.  When we got ours all the rocker switches were out because the p.o. wanted new ones.  He had the new ones but I am not sure if he knew how to put them all back or what but I had to figure out whats up under there... Any way, the way I remember the fuel guage, One wire comes from each tank to the switch then the switch chooses which one goes to the guage.... as far as our duel, mom, main switch, I guess he, the p.o., couldnt find one that had the momemtary position so now I have only a connected or not connected switch... But what seems wierd on yours is that the tank senders use a ground signal. so the mom. duel, switch shouldnt effect the guage unless you are turning off the power to the guage when you flip the switch...but if this was the case then I think all the guages would be off... like the water and oil... I cant say for sure but that is what I have figured out by rewiring my switches....- Henry



From: Moesyn
Sent: 21/03/2008 10:44 AM

In the Itascas is the solenoid mounted up under the dash behind the shift lever (hence "tucked up in the corner") or in another corner? I can't seem to find mine on our 76 Brave, even though the dash photos look almost identical. Thanks!

Dave


 
From: AlbuqHenry
Sent: 21/03/2008 11:38 AM

on our brave it is on the front wall looking straight forward from the parking brake on the left....... If you follow the wire from the switch it should lead to it... I had to seperate all the wires from each other in order to follow them back... I cut all the zip ties.- Henry
 


From: AlbuqHenry
Sent: 21/03/2008 11:44 AM

I read your post again... On mine mounted on the dash, right behind the shifter, not on the front wall is a solenoid also that one is for the fuel tank selector or the fuel guage selector.  The one for the fans is on the front wall... it is bigger than the fuel one.... kinda behind the fues panel... it looks just like the pics...-Henry



From: AlbuqHenry
Sent: 21/03/2008 11:50 AM

I went out and looked at the winnie... It is behind the board that the dimmer switch is mounted on.  I think you will have to remove this board.  When I got our winnie it was already out.  I had a heck of a time trying to get it past the pedals... I ended up cutting it in half... -Henry


 
From: Moesyn
Sent: 23/03/2008 12:02 AM

Thanks so much for the info Henry. I'll find that bugger first thing in the AM! I'm glad it seems to be a readilly-available part. 



From: oldodger
Sent: 23/03/2008 4:55 AM

My heater fan,  wipers and windshield washer on my 77 chieftain are live at all times...modification or standard wiring?I bought new wiper blades last fall and haven't turned a wheel and wipers are all cut up...sun effects I guess.Oh well...still great to sleep in...Have to get back in the house when mercury drops to -10 canadian or 10 american !! 



From: denisondc
Sent: 23/03/2008 5:52 AM

Having those accessories live at all times would have been a modification I think. It could have been because the original ignition switch developed a bad connection; the heater fans can draw a great deal of current. Seems harmless enough. No one is likely to walk away accidentally leaving the wipers sweeping. It would be more likely to leave it with the heater fan on a low setting.



From: Moesyn
Sent: 29/03/2008 2:06 AM

I finally located the relay behind the dimmer switch/kickboard and replaced it with a new identical one (three terminal) from NAPA and... the fans work again!  I couldn't have done it for the grand total of $22 and 20 minutes had it not been for this great post/photos and assistance from all of you. Many thanks!! 



From: Moesyn
Sent: 10/04/2008 12:14 AM

Hi All,

Well, back  to the drawing board!  The three-terminal replacement relay I installed (NAPA Echlin ST82) worked great for three days of our trip, then inexplicably quit on the last day. It still gets hot to the touch (?!) but the fans won't turn on. Since it worked fine for a few days it might just be a bad unit (?) but before swapping it out with another I'm wondering if the PO might have had the main terminal wires reversed--which would mean that I still have them reversed-- and if this matters with these solenoids (i.e. if wiring the main terminals "backwards" could allow it to run properly for a few days but eventually burn outas mine did?)   Here is the detail:

After the fans quit again, I went over my wiring with both old and new solenoids in hand, and compared mine to Pinballlarry's original photos and description of his old solenoid and wiring. I soon realized that my main terminals were and are wired in reverse compared to his. On his rig the left terminal "pinkish wire" is the hot lead coming from the battery, while the right terminal greyish wire connects to the fan switch. On my rig with that same original solenoid that his photos depict, the right terminal was connected to the battery, while the left terminal was connected to the fan switch. On both of our original solenoids the right terminal is stamped "BATT" on the housing (you can see it in his photo as well if you look closely) so I thought I had this wired correctly. Yet, on his rig as per his explanation, the "BATT" side was wired to the fan switch... and I assume he replicated this wiring pattern with the new solenoid (?). 

In any case, because my new NAPA solenoid wasn't marked with anything on either side, I replicated the existing pattern I had (right terminal from batt, left terminal to fan) and it worked for a while, but then quit. I guess my question really boils down to whether or not these solenoids have specific terminals (one dedicated to 12v in, and one to fan) or if they are just a switch. If it is the latter, then is it reasonable to suspect that the new solenoid was just a bad apple and just replace it again?

Many thanks!

Dave



From: AlbuqHenry
Sent: 10/04/2008 6:10 AM

I wouldnt think it mattered on the in and out, I thought it would be just open and closed but who knows... lol  I will look at mine and see which is in and out and let you know... one other thing.  If it is getting warm that means it is getting power to the solinoid,  did you double check to make sure you are getting power from the batt. at the same time.  Mine is connected to a thermal breaker in the batt. compartment then to the batt.  maybe yours is opening.  but then it would probably run then stop then run and so on intermitant..I will let you know how mine is hooked up-Henry



 
From: Elandan2
Sent: 10/04/2008 12:20 PM

Ensure that the solenoid you are using is a "continuous" duty unit.  Although they look the same as a Ford starter solenoid, they are not the same.  A starter solenoid is not rated for "continuous" duty and will burn out quite quickly.  If yours is wired the same as mine, the solenoid is energized whenever the ignition is in the "on" position even though the fans are turned off.   Rick   



From: AlbuqHenry
Sent: 10/04/2008 3:23 PM

I looked at mine as it sits the right one goes to the batt. one on the left goes to the heater swich.-Henry



From: Moesyn
Sent: 10/04/2008 4:37 PM

Thanks for the info guys! I called NAPA and as it turns out Rick was right on the money: the ST-82 that I put in is NOT continuous duty. The ST-95 is the one that I need... three post continuous! I'll install one tonight and report back. Thanks again! I can't tell you how much I appreciate the tips/info I have learned here. 



From: Moesyn
Sent: 11/04/2008 3:08 AM

The ST-95 seems to have done the trick.  The fans blow at all three speeds once again. Now for the longevity test...