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Eric
Eric, Automotive Repair Shop Manager
Category: Car
Satisfied Customers: 31605
Experience:  Automotive Repair Shop Manager, Technician/JA Mentor
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I have A 1998 S-10 LS 4.3 my a/c compressor has a switch in

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I have A 1998 S-10 LS 4.3 my a/c compressor has a switch in the back of it and I am not sure it is what should be in it . It is green, the a/c has never worked from the day I bought it. Installed all new Compressor,condenser,dryer and orfice tube, I took blower motor out cleaned and checked it-its fine. What do you think
Welcome! My name is XXXXX XXXXX I will do my best to assist you with this problem.
the refrigerent is filled to the correct amount correct ?
when the engine is running and you turn on the A/C the compressor will not turn on at all ?
Customer: replied 3 years ago.

yes ,compressor will not kick on.

ok do you have a test light? multi meter ? any paper clips on hand ?
Customer: replied 3 years ago.

paper clips yes

no test light or multi meter ?
also start the truck up turn the A/C on and the blower motor on
unplug the low switch in the accumulator and jump the 2 terminals with a peper clip in the connector you unplugged and see if it will run
if it still will not run leave it running plug that back in and then unplug the connector for the high pressure cut off switch back of compressor area (light blue and darkgreen/white wires ) jump that connector and see if it runs
Customer: replied 3 years ago.

I jumped low switch connector , no compressor. I jumped high switch connector , no compressor. I looked at all fuses and they are good. With max a/c on I can not here compressor engage, blower motor works fine

ok do you have a test light or a multi meter on hand ?
Customer: replied 3 years ago.


no cant find it

lets see if another expert has any ideas

the next step is to check for voltages and grounds and see what's missing

Customer: replied 3 years ago.


I will get a volt meter and test them tomorrow as I work nights.

Hi,

Different expert here, once you get the voltmeter and are ready for testing, let me know and I will walk you thru it
Customer: replied 3 years ago.


I have voltage meter now ready when you are


 

Hi,

Ok, with ac on, at the compressor harness connector check for 12v on the dark green wire and good ground on the black wire
Customer: replied 3 years ago.

I am not getting 12 volts out of harness

HI,

Ok, because fuses can appear intact when they have failed, use your voltmeter and check for 12v across the AC fuse and the IGN E fuse in the engine compartment fuse box

If ok, next swap out a relay with the AC compressor relay in the same fuse box. We can only do this to test the relay as a Tech2 scan tool is needed to actually test the relay itself, so swapping for another relay will take its place in testing
Customer: replied 3 years ago.

Ok I will try this as soon as I have time as I am out of town for weekend. and I have to get to work now. I will get back to you thanks for your help.

HI,

Ok, I am here everyday, so no problem, but I want to go ahead and give you the rest of testing procedure

Ok, If fuses and relay is good, then you will need to test the following at the VCM(vehicle control module).

with engine idling and ac on, backprobe the dark green with white striped wire at pin #1 on connector C3 at the vcm for 12v

if 12v present, then repair dark green wire with white stripe between the VCM and the AC relay(cavity #2)

If not present, then check pin#25, dark green with white wire, as well as pin#30, dark green wire for 12v.

If 12v present at both, replace the VCM

If 12v not present at the dark green wire(pin30), check for 12v at dark green wire at the ac low pressure switch. If present, repair wire between low pressure switch and the VCM

If 12v not present on the green with white striped wire (pin 25), then check for 12v at the high pressure switch at the greeen with white stripe wire. If 12v present, repair the wire between the high pressure switch and the VCM

If 12v not present, then check for 12v present on the light blue wire at high pressure switch. If present, replace the high pressure switch. if not, then check for 12v at the light blue wire at the ac control switch. If present, repair light blue wire.





VCM location and C3 connector location



graphic


C3 connector pinout

graphic
Eric, Automotive Repair Shop Manager
Category: Car
Satisfied Customers: 31605
Experience: Automotive Repair Shop Manager, Technician/JA Mentor
Eric and other Car Specialists are ready to help you
Customer: replied 3 years ago.


Eric, the#1 pin on C-3 connector has 12 volts, I would like to jump this wire can you tell me where the a/c relay (cavity #2) is or give me a diagram of it Please.

Customer: replied 3 years ago.
Relist: Answer quality.
I 'm asking for more information on the answer as to where the a/c relay(cavity #2) location is because I could not see it in the answer that was sent to me.
Hi,

ac relay is in the engine compartment fuse/relay box

let me see if I have a diagram of its location in the fuse/relay box or have a connector pinout for fuse/relay box wiring connectors

Hi,

relay location

graphic

 

the wire you want, the dark green/white wire for cavity 2 on the relay is in the c2 connector, at pin location B4, on back of fuse box