AC and heat not working. Head unit has no display
07-06-2007, 11:34 AM
#1
6th Gear
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Location: Nashville Tennessee
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AC and heat not working. Head unit has no display
Problem solved
Problem was with the programmer that controls the head unit. The connector is located on top of the unit and moisture ate away at one of the pins and corroded the others. I replaced the pin by soldering in a paper clip (perfect size) and cleaned the corrosion. Came on instantly and works great. Thanks to jfb for the tip.
Cooper
The electronic (C68) A/C head unit on my 1992 convertible does not display information but is backlit. All the fuses read continuity but I measure zero voltage on "R INST" and "HTD MIR". All other fuses read 12 volts. I did jump 12 volts to the two that read 0 and nothing happened. I also checked the fusible links by the battery. Are there others I need to check?
I pulled the head unit but have not pulled the programmer (please let me know the best way to get to it if you feel it is bad). I measured 12 volts between pins 1 and 10, 1 and 2.
I washed the engine on Tuesday and that is when the A/C quit working temporally. When I noticed it was not working, I turned the ignition off and back on. The display read segments horizontally. I turned it back off and on and the system started working again. It worked the remainder of the night but will not come on today. I did have one other issue in the past about 2 months ago. The outside temperature stuck at 45 degrees for about 15 minutes then started reading correctly.
I am hoping the 2 fuses that have 0 volts will help diagnose the problem. Any help will be appreciated.
Cooper
Problem was with the programmer that controls the head unit. The connector is located on top of the unit and moisture ate away at one of the pins and corroded the others. I replaced the pin by soldering in a paper clip (perfect size) and cleaned the corrosion. Came on instantly and works great. Thanks to jfb for the tip.
Cooper
The electronic (C68) A/C head unit on my 1992 convertible does not display information but is backlit. All the fuses read continuity but I measure zero voltage on "R INST" and "HTD MIR". All other fuses read 12 volts. I did jump 12 volts to the two that read 0 and nothing happened. I also checked the fusible links by the battery. Are there others I need to check?
I pulled the head unit but have not pulled the programmer (please let me know the best way to get to it if you feel it is bad). I measured 12 volts between pins 1 and 10, 1 and 2.
I washed the engine on Tuesday and that is when the A/C quit working temporally. When I noticed it was not working, I turned the ignition off and back on. The display read segments horizontally. I turned it back off and on and the system started working again. It worked the remainder of the night but will not come on today. I did have one other issue in the past about 2 months ago. The outside temperature stuck at 45 degrees for about 15 minutes then started reading correctly.
I am hoping the 2 fuses that have 0 volts will help diagnose the problem. Any help will be appreciated.
Cooper
Last edited by ooxxoox; 07-10-2007 at 11:43 AM. Reason: Problem solved
07-08-2007, 02:06 AM
#5
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Location: Cincinnati, Oh USA
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First remove the head unit and use a Q tip and electrical contact cleaner and wipe the pins on the plug in the rear of the unit and plug it back in and try it. If you still have trouble, remove the circuit board from the head unit and wipe the gold plated fingers on the edge of the printed circuit board. Also wipe the v shaped flat springs that make connection to the top of the circuit board. Put it back together and see if it works. If not, you likely have a circuit problem that a repair center needs to look at for you.
