HVAC control electrical

F1LOCO · 10-13-2022, 09:35 AM

So, whilst I had the dash apart to chase more electrical gremlins, I removed the HVAC panel and replaced it with RENNLINE's. While out I lightly sanded the two contact points and the copper plates. I used my old distributer point files. Got it all hooked back up and noticed that the light will switch on at "I" but then go out by the time I am all the way to position "III" - so I stuck my fingers in and pressed as best I could to make sure there is good contact, but with the same result. I thought, hmmm, maybe some good carbon conductive grease would do the trick, so I put a dab on and went back and forth with the top slider. Started the car, and though better, it still seems disconnect if it is all the way to position "III" - before putting it in I checked to be sure the slider kept the points of contact in contact throughout the range and appeared work fine? More disconcerting is the fact that the light for fan appears to be on, but dim, when it is all the way to the left. I do notice it gets brighter once it hits position "I" and though not as dim, tends to dim a in position "III" - anyone have any ideas what is going on? Even with it brightly lit and in position "II" I go to the frunk and swear the blower motor is not working. That said, I do have AC (though that's another project to tackle). Is that a completely separate blower motor? When I switch it on, it does appear to push some luke temperature air through the vents in the dash.

timmy2 · timmy2's Garage

Check continuity between the single pad and each of the 3 speed pads as you slide the controller from off to full speed.
I just repaired one that the slider contact area of the 2 and 3 speed pads had sunk into the plastic due to over heating. I had to melt the plastic with a thin soldering iron and lift the individual plates, then back fill the void in the plastic with new plastic. (I used a black tie wrap to melt and fill.
Also check the wire soldering on the bottom feed to the main single power pad . (And the others)
Photo is after repairs made. You can see some “roughness” on the painless plastic area around 2 pads.

F1LOCO · 10-13-2022, 10:55 AM

Sigh ... dreaded removal and reattachment of the cables. That is the one of the worst jobs so far. Still waiting on new clips for the front box so I a can get them all dialed and locked in.

eastbay · 10-13-2022, 11:15 AM

Pull the radio and you can get to it pretty easy. Check for a bend at the metal spot I circled on Timmys picture.

I had a car where a hamfisted POs radio install bent the contact plate way down and nothing worked.

You can tweak the plate up for better contact also, but only bend the metal.

F1LOCO · 10-22-2022, 08:05 AM

So I managed to get it all put back together. I think the motor is gone as I do not hear it nor does it even vibrate with the power is engaged, yet with the AC switch, I can feel air out of the vents? Does this make any sense?

Also, query, I now notice my toes are on fire after about 10 mins of driving here in FL? I run the center slider to the right and the top/bottom to the left. Thought's on what went wrong with the cable re-install? I made sure everything was adjuster to full open/close with full slider movement?

timmy2 · timmy2's Garage

Heat on/off is controlled by the levers or auto heat beside the brake handle. Opens and closes the flapper valves at the engine compartment.
Don’t know the year of your car. It would help.
Is it warm outside air coming in? That is controlled up front and will be your dash lever adjustments.

F1LOCO · 10-23-2022, 10:07 AM

Thanks, will have to get on it on the ramps and see what is binding. I tried pulling and pushing the levers by the Erake a few times with no success. I wish it were just warm air (I do live in FL) - this is burn your toes off hot under the dash.