Too much power to ac control module

[PlayingWithTBI]

Could it be such a thing like your compressor clutch relay, or whatever that switch activates, is shorted out somewhere?

 

[skylark]

Here's a pic of where the module burned out this time after the fix (aka: glob to the left. The burned out path is linked to the ac switch on the module. Hopefully this will shine some light on my problem.

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If that doesn't shine a light then perhaps the electrical fire after the magic smoke comes out will help!

 

[RANDALL COOK]

What was the "I tried the fix with the control module, which lasted right up till I gave it a bit of throttle.." that you refer to? What is that large non-OEM glob of solder on the board? While alternators can create a very high voltage, most regulators maintain between 13.8-14.8 volts. How many boards have you burned up, and were they all new? Before I would buy another new board, I would buy a new voltage regulator, or alternator, if its all one unit. I would also check to see than no spark plug wires (if it has any) are laying against any other wiring. Then I would get a good digital voltmeter and connect it to the + post on the fuse panel and the negative to the steel on the engine and see what you have. I would not trust Firestone.

 

[AK49BWL]

The A/C switch you say? That switch sends voltage out pin10 (light green wire) of the long gray connector on the end of the controller. This wire goes to your low pressure cutout switch on the low side line at the compressor, then to the PCM. It does not actuate the clutch or relay, the PCM does that. I'd check for shorts at that switch on the lines at the compressor and in the wiring to it.

 

[HawgHunter]

Thank y'all for the great input. I've got myself a decent multi-meter https://testmeterpro.com/innova-3340-multimeter/ and will be doing more testing tomorrow as work allows. AK49BWL, I actually put a 10a fuse in the wire a while back in the hopes the problem was coming from that exact light green wire....and would blow the fuse instead of the module. I did do some pocking around under the hood today at the wiring and do believe that I should start looking there for shorts...as the wiring is 22 years old.

I will keep y'all posted...thank you again.

 

[HawgHunter]

Alright folks...been a long week at work and I got a lot done, but not so much on my ac problem.However, I was able to have a buddy of mine take a look at my truck. He noticed a connector inline with the compressor clutch was basically just falling apart and possibly causing a short. So, I will be replacing that today while also looking for more old/bad connections and frays in the lines. I will post pics and more details later.

 

[Joey0278]

I am having the same issue and cannot figure it out ? Changed all switches and sensors and compressor today and still burns up the control head ?

 

[Joey0278]

Just an update, i cut the light green wire at the compressor and at the switch inside and ran a jumper lead to test it and it worked good so i ran a new wire and it seems to be working ok ! That light green wire goes into the big harness and i was not gonna track it down under the dash ! Seems like a short to ground because everytime i put a good switch in it would burn it up but not now.