A/C Diagnostics

Hey guys,

In the process of trying to get my car back in tip-top shape and have begun working on my ac. When i bought the car the CC unit was only working on high and ac didn't blow cold at all. I replaced the CC unit with an SoS unit. And just got the AC charged today with r134a. However, my heater valve doesn't move at all when i turn the CC from hot to cold, though the valve can be pushed by hand. With the valve in the closed position, the AC still blows hot. However we took some hose clamp pliers and put them on the heater hose right before the valve to close off the hose completely and it blows slightly cold? Does this sound like a motor problem or what?

Bump. Still need help. Cable on heater valve still doesn't move, is there a motor connected to the cable that's bad?

Cable only.
It may suck but disconnect both ends and flush the cable with a thin lubricant like Tri-Flo or ... and work the cable till it's free.
Be sure it's not just a stuck heater valve.

Cheers
nigel

Do I have to remove the dash to get to the other end? I can move the cable at the heater valve manually and I already adjusted it there.

Start on page 22-69 of the shop manual.
It explains how the drive motor and the cable works.
You may have a bad motor or perhaps the cable slipped off the motor.

JD Cross said:

Start on page 22-69 of the shop manual.
It explains how the drive motor and the cable works.
You may have a bad motor or perhaps the cable slipped off the motor.

Click to expand...

So i got a new motor and it still doesn't move when changing between cold and hot. I bench tested the motor off the car and the motor ran and moved when i gave it battery power and ground, but in the car it does nothing. Any more ideas?

elijahcole92 said:

So i got a new motor and it still doesn't move when changing between cold and hot. I bench tested the motor off the car and the motor ran and moved when i gave it battery power and ground, but in the car it does nothing. Any more ideas?

Click to expand...

Have you run the self-diagnosis circuit check?

Yeah it gave me an error for the heater vavle control motor.

elijahcole92 said:

Yeah it gave me an error for the heater vavle control motor.

Click to expand...

So the self-diag gave you a valve control motor error.
You replaced the motor and bench tested it so it worked with bench supplied voltage.
Would the next step be to use a multimeter to test if power is being sent to the motor when the CCU is sending a signal to open or close the valve.
No signal would suggest CCU problem?
Briank is the guru for this.

JD Cross said:

So the self-diag gave you a valve control motor error.
You replaced the motor and bench tested it so it worked with bench supplied voltage.
Would the next step be to use a multimeter to test if power is being sent to the motor when the CCU is sending a signal to open or close the valve.
No signal would suggest CCU problem?
Briank is the guru for this.

Click to expand...

Well i think my issue is solved. I decided to test the motor while plugged into the car but not hooked up to the heater and found that the motor still wouldn't work. So I started going through the SM troubleshooting steps and noticed the grey plug plugged in had totally different wire colors than the SM was telling me to check, then i found a blue plug nearby that had the correct colors plugged it in and BAM the new motor started working, tried the old one and it didn't work so i guess it was actually bad! Thanks so much for your help. Still don't understand why the correct plug is blue and the plug on the motor is gray?

elijahcole92 said:

Well i think my issue is solved. I decided to test the motor while plugged into the car but not hooked up to the heater and found that the motor still wouldn't work. So I started going through the SM troubleshooting steps and noticed the grey plug plugged in had totally different wire colors than the SM was telling me to check, then i found a blue plug nearby that had the correct colors plugged it in and BAM the new motor started working, tried the old one and it didn't work so i guess it was actually bad! Thanks so much for your help. Still don't understand why the correct plug is blue and the plug on the motor is gray?

Click to expand...

Well done!
Nothing quite as rewarding as sticking to a problem until you solve it.