Dont know if its been posted but thought it could help somebody. Especially seeing those 95 modules or adapter harnesses climb in price. Ive tried amazon control modules and heat doesnt work, etc.
If you have following symptoms in your truck
1) A/C button dont light up
2) Recirc won't dont light up
3) Mode of operation knob has no effect (air comes only to floor for example)
4) Rear defog button works normally
5) Temp and fan speed knobs works normally
The problem is a transistor in the module (red- in pic below) 2857, you can replace it with the same part number or choose a more common PNP transistor. 4687 (blue) is also a PNP transistor and can be replaced with same as part number as red. The 4692 (purple) is a NPN if working on a 95 module it has 2 of these. 95 has 4 transistors and 96+ only has 3. These you can use a 2n4401 or equivalent NPN transistor. I havent ran into a bad one its always the one in red only. If transistor blows again (opens) there is a short circuit on your light green wire that sends power to your a/c components. This module is a 96+ with the 95 adapter harness as 95 is a one year only module and as stated above will work on 95 modules as well.
To test transistor you need to pull it out of the circuit and keep the negative lead of multimeter on the base and put red lead on emitter should show .4-.9v then move red lead to collector and should show .4-.9v if it shows 0v then its open. For the NPN transistors the leads would be reversed. Not gona get into detail but tbis is how you would test to see if you have a PNP or NPN transistor as well.
If you have following symptoms in your truck
1) A/C button dont light up
2) Recirc won't dont light up
3) Mode of operation knob has no effect (air comes only to floor for example)
4) Rear defog button works normally
5) Temp and fan speed knobs works normally
The problem is a transistor in the module (red- in pic below) 2857, you can replace it with the same part number or choose a more common PNP transistor. 4687 (blue) is also a PNP transistor and can be replaced with same as part number as red. The 4692 (purple) is a NPN if working on a 95 module it has 2 of these. 95 has 4 transistors and 96+ only has 3. These you can use a 2n4401 or equivalent NPN transistor. I havent ran into a bad one its always the one in red only. If transistor blows again (opens) there is a short circuit on your light green wire that sends power to your a/c components. This module is a 96+ with the 95 adapter harness as 95 is a one year only module and as stated above will work on 95 modules as well.
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To test transistor you need to pull it out of the circuit and keep the negative lead of multimeter on the base and put red lead on emitter should show .4-.9v then move red lead to collector and should show .4-.9v if it shows 0v then its open. For the NPN transistors the leads would be reversed. Not gona get into detail but tbis is how you would test to see if you have a PNP or NPN transistor as well.
You must be registered for see images attach
