Hi all,
I've got my FIL's 1988 Cadillac Brougham (the RWD one) in quite fantastic condition. The one issue with it is the ECC head will not let me select a temp lower than 75 deg. I can select higher, just not lower. When in "Auto" the system does work as far as the fan ramping up and back down again when the selected temp is reached... so long as it is 75 or higher.
I connected my Snap-On Solus Pro up and noted that it showed:
Low A/C Press.... YES
A/C Request.......Yes
A/C Clutch...........Off
I figured that it may just be low on charge. I put 2 pounds virgin R12 in whilst jumping the Low A/C Press connector in order to get the clutch to engage (it did). The Solus Pro showed:
Low A/C Press.......No
A/C Request.........Yes
A/C Clutch..........On
Feeling the air conditioning lines, it sure did seem like everything was circulating as it should. When I went to select a lower temp than 75, I was still not able to. Higher, yes. So, still the same fault.
I disconnected the jumper and remade the connection to the low press switch and noted that the original fault remained. I still cannot select a temp lower than 75.
Low A/C Press......Yes
A/C Request.......Yes
A/C Clutch..........Off
End result here is that I know that I have good R12 and pressure at this point. So, do I go after the ECC control head, programmer, power module? I do have all the GM manuals including wiring. GM never discussed what to do when a selection of temp was not available. Basically the troubleshooting tree says "run the temp full hot and this should happen; run the temp full cold and that should happen but not what to do if one of those selections didn't operate.
Back probing connectors is next but I'm hoping someone has some good GM experience to guide me.
Thanks in advance,
Olds G's
I've got my FIL's 1988 Cadillac Brougham (the RWD one) in quite fantastic condition. The one issue with it is the ECC head will not let me select a temp lower than 75 deg. I can select higher, just not lower. When in "Auto" the system does work as far as the fan ramping up and back down again when the selected temp is reached... so long as it is 75 or higher.
I connected my Snap-On Solus Pro up and noted that it showed:
Low A/C Press.... YES
A/C Request.......Yes
A/C Clutch...........Off
I figured that it may just be low on charge. I put 2 pounds virgin R12 in whilst jumping the Low A/C Press connector in order to get the clutch to engage (it did). The Solus Pro showed:
Low A/C Press.......No
A/C Request.........Yes
A/C Clutch..........On
Feeling the air conditioning lines, it sure did seem like everything was circulating as it should. When I went to select a lower temp than 75, I was still not able to. Higher, yes. So, still the same fault.
I disconnected the jumper and remade the connection to the low press switch and noted that the original fault remained. I still cannot select a temp lower than 75.
Low A/C Press......Yes
A/C Request.......Yes
A/C Clutch..........Off
End result here is that I know that I have good R12 and pressure at this point. So, do I go after the ECC control head, programmer, power module? I do have all the GM manuals including wiring. GM never discussed what to do when a selection of temp was not available. Basically the troubleshooting tree says "run the temp full hot and this should happen; run the temp full cold and that should happen but not what to do if one of those selections didn't operate.
Back probing connectors is next but I'm hoping someone has some good GM experience to guide me.
Thanks in advance,
Olds G's