A/C Electrical Help !

[hoosierdaddy]

I removed the a/c switch's and center console on my 77S to install my short shift , as I was putting things back together I found my compressor wasn't engaging when I turned the fan switch on . Thats the first problem the second is I noticed the + wire going to the fan switch was getting very hot and also the fuse for the fan was quite hot . I'm more concerned about the hot wire than I am about the compressor not engaging . Can anyone tell me the wiring order for the fan switch ? What else should I look for ?

[kuehl]

If it worked before it should work again!,,,,, provided:
A) The fan switch is connected properly, and
B) The aluminum tube coming out of the thermostat (LH switch)
was not damaged.

There is a schematic off the PP Main page to help you trace the circuit.

[DonMo]

I had my fan switch go bad and it got real hot, like melting plastic hot. I put a new switch, problem went away.

[hoosierdaddy]

kuehl
The tube coming out of the thermostat switch is damaged . Will this require a new switch or is there a repair ? Would this have any affect on the + positive wire to the fan switch getting hot ?

Jim

[jdowty3]

Jim, for a temporary fix, you can jump the 2 terminals on the thermostat switch. This should cause the compressor to engage when the fan switch is turned to any setting but zero.

[hoosierdaddy]

Jim
Thanks for the input , I had already jumped the two wires to make sure the compressor would engage . My real concern is with the wires getting hot . I'm starting to believe the blower motor is drawing to many amps which would mean it needs to be replaced . What puzzles me is the blower seems to be working perfect .

[kuehl]

check the amp draw on the motor.
you could splice in a 15 amp fuse between the fan speed control resistor pack and the fan motor.

inspect the fan speed resistors (spring type) located in the evap. inlet under the passg. side foot board, they usually have bi-metal set of contacts to break when things get hot down there, see if the contacts are welded.

[jdowty3]

I had a similar problem a couple years ago. The heat build up in the 12V wire and fan switch started to damage (soften) the housing and terminal mounts. I replaced the switch with one from our host and no more overheating.

[kuehl]

Switch replacement is not uncommon, lots of amps need to move through it.

However, if you got the new Kuehl Variable Speed Fan Controller ........ !

[hoosierdaddy]

Jim
That is the same problem I'm having and I've found nothing else wrong. I guess I'll have to replace the switch for peace of mind , that shouldn't cost but $5-$6 but maybe for a couple of dollars more I could get the new Kuehl Variable Speed Fan Controller .
Thanks everyone for your input .
Jim

[hoosierdaddy]

Kuehl
I did check out your fan switch it sounds pretty trick compared to the oem but my next a/c improvement will be a new compressor . In defense of my old system it still works better than I expected . The other day we had a 100 degree heat index it was really comfortable inside the car , it will never make you cold in it's current state but it's very useable .
Jim

[kuehl]

If your happy with the stock fan speeds, the oem switch is not that expensive; maybe a 911-613-243-00

past PP tread
a/c fan switch wiring help