'92 climate control unit dead and code C25
Thread Starter
8th Gear
Joined: Sep 2012
Posts: 8
Likes: 1
From: Scappoose, OR
'92 climate control unit dead and code C25
Hi,
My first post - I need some help. I have the flashing "SYS", and my electronic climate control unit only has backlight, no readout, no operation of heating or AC.
This happened just before the heater core started leaking. I've replaced the heater core, over about 3 months (I don't know what I am doing, but persistence and the forum got me through).
I was hoping that during the heater core replacement I'd find the wiring problem causing my SYS and climate control problems, but no luck. The car does have an after-market stereo with some questionable wiring.
Codes are:
C25 - Courtesy lamp relay coil circuit open or shorted to ground
H25
H72 - LCD dimming output circuit open or shorted to ground
H74 - LED display dimming output circuit open or shorted to ground
---
---
9
H71 - ? LCD dimming output circuit shorted to battery or CCM internal open circuit
---
10
The courtesy lamp relay seems OK. How do I test it? How else to isolate the issue with this code?
Any ideas on the climate control head unit? I don't want to replace it for a couple hundred dollars unless I know that is what's wrong.
Thanks in advance for any assistance.
Scott
My first post - I need some help. I have the flashing "SYS", and my electronic climate control unit only has backlight, no readout, no operation of heating or AC.
This happened just before the heater core started leaking. I've replaced the heater core, over about 3 months (I don't know what I am doing, but persistence and the forum got me through).
I was hoping that during the heater core replacement I'd find the wiring problem causing my SYS and climate control problems, but no luck. The car does have an after-market stereo with some questionable wiring.
Codes are:
C25 - Courtesy lamp relay coil circuit open or shorted to ground
H25
H72 - LCD dimming output circuit open or shorted to ground
H74 - LED display dimming output circuit open or shorted to ground
---
---
9
H71 - ? LCD dimming output circuit shorted to battery or CCM internal open circuit
---
10
The courtesy lamp relay seems OK. How do I test it? How else to isolate the issue with this code?
Any ideas on the climate control head unit? I don't want to replace it for a couple hundred dollars unless I know that is what's wrong.
Thanks in advance for any assistance.
Scott
Thread Starter
8th Gear
Joined: Sep 2012
Posts: 8
Likes: 1
From: Scappoose, OR
Dead Climate control head unit
Hi,
Trying again...Any one ever have a climate control unit with just the backlight, no readout, no operation? Should I just replace the unit?
Thanks,
Scott
Trying again...Any one ever have a climate control unit with just the backlight, no readout, no operation? Should I just replace the unit?
Thanks,
Scott
Hi,
My first post - I need some help. I have the flashing "SYS", and my electronic climate control unit only has backlight, no readout, no operation of heating or AC.
This happened just before the heater core started leaking. I've replaced the heater core, over about 3 months (I don't know what I am doing, but persistence and the forum got me through).
I was hoping that during the heater core replacement I'd find the wiring problem causing my SYS and climate control problems, but no luck. The car does have an after-market stereo with some questionable wiring.
Codes are:
C25 - Courtesy lamp relay coil circuit open or shorted to ground
H25
H72 - LCD dimming output circuit open or shorted to ground
H74 - LED display dimming output circuit open or shorted to ground
---
---
9
H71 - ? LCD dimming output circuit shorted to battery or CCM internal open circuit
---
10
The courtesy lamp relay seems OK. How do I test it? How else to isolate the issue with this code?
Any ideas on the climate control head unit? I don't want to replace it for a couple hundred dollars unless I know that is what's wrong.
Thanks in advance for any assistance.
Scott
My first post - I need some help. I have the flashing "SYS", and my electronic climate control unit only has backlight, no readout, no operation of heating or AC.
This happened just before the heater core started leaking. I've replaced the heater core, over about 3 months (I don't know what I am doing, but persistence and the forum got me through).
I was hoping that during the heater core replacement I'd find the wiring problem causing my SYS and climate control problems, but no luck. The car does have an after-market stereo with some questionable wiring.
Codes are:
C25 - Courtesy lamp relay coil circuit open or shorted to ground
H25
H72 - LCD dimming output circuit open or shorted to ground
H74 - LED display dimming output circuit open or shorted to ground
---
---
9
H71 - ? LCD dimming output circuit shorted to battery or CCM internal open circuit
---
10
The courtesy lamp relay seems OK. How do I test it? How else to isolate the issue with this code?
Any ideas on the climate control head unit? I don't want to replace it for a couple hundred dollars unless I know that is what's wrong.
Thanks in advance for any assistance.
Scott
