how to test a.c. control unit

Asked by truckgal Jul 27, 2011 at 11:31 AM about the 2000 Chevrolet C/K 3500 Crew Cab LB 4WD

Question type: Maintenance & Repair

Hi everyone! My a.c. is not working and I beleive it is the control unit but need some advice if I am on the right track or way off. I have Jumped the relay to engage the compressor clutch and it did engage. So that leaves me with is it the contol unit? and if so, how do I test it? any answers would be great. Thanks

2 Answers

5,735

do u have a signal coming out of the module to turn on the relay for ac ? get a wiring diagram and look for power and ground supply to unit but i dont think that is the problem....... there is a low pressure cut off switch i think by the accumulator but they may have changed it around but look at a diagram look for the wires should be on the lines some where and find out the power and signal wire to the computer and jumper those terminals and then turn on the ac like u normally would if it goes on it is because the system pressure is low and control unit wont turn it on to save compressor from destroying itself if it does u have to get dye injected to the system and r-134a and run the system and use a black light to find the leak then repair and charge system and enjoy

2 people found this helpful.
45

I have the same problem with my 99. take off the control unit itself and look at the leads on the circuit thing. the temp one on mine fried off so that could be the problem

2 people found this helpful.

Your Answer:

CarGurus Experts

  • #1
    Joe_2019
    Reputation
    420
  • #2
    Gene Arnett
    Reputation
    410
  • #3
    Keith Massey
    Reputation
    220
View All

Find great deals from top-rated dealers

Search

Related Models For Sale

Used Chevrolet Silverado 3500
1 listings starting at $12,999
Used Chevrolet Silverado 2500HD
16 Great Deals out of 1,149 listings starting at $8,999
Used Ford F-350 Super Duty
42 Great Deals out of 2,594 listings starting at $8,888
Used Dodge RAM 3500
28 listings starting at $13,888
Used GMC Sierra 3500
3 listings starting at $8,999
Used Ford F-150
296 Great Deals out of 15,534 listings starting at $1,712
Used Ford F-250 Super Duty
28 Great Deals out of 1,155 listings starting at $8,995
Used Ford F-450 Super Duty
5 Great Deals out of 147 listings starting at $27,995

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.