Question-------------------------
Followup To
Question -
I have a 1995 Concord with automatic tempature control. I get this error code: "36 ATC head command failure".
I have replaced the head once and replaced the relay on the head to try to correct the problem. What else can be done for it?
I am thanking you in advance for your assistance.
Happy New Year!
Answer -
Hi Melvin,
I don't have the 'Body Diagnostic Manual' that gives the steps for each trouble code's correction, according to the info in the '94 shop manual that I do have. But I suspect that you might at least want to verify the connections between the control unit and all of the components are patent, using an ohmmeter or continuity tester. I have the wiring diagram for the '94 unit which is probably the same as for your car and can xerox and snail mail it to you for that purpose. How is the unit misbehaving? How long did it operate properly after you did the earlier servicing? If you wish to have the diagrams just give me a postal mailing address.
Roland
Roland:
Thank you for your speedy reply. I have the wiring manual. After replacing the unit, it took about 3 months for it to malfunction again. The malfunction is that no lights or controls function on the unit. The A/C compressor functions, the fan runs at a slow moderate speed and produces only hot air. I have taken the control unit out and sodered some of the wires on the main board that appeared loose. I have been able to wiggle the wires in the wireing harnes where it plugs into the unit and it would function again. The wiggling of the wires no longer helps. Most recently, I have just tapped the casing of the control unit with the handle of the screw driver and it begins to function and will work perfect for a time. Yesterday, I drove about 500 miles with it working, I stopped for gas and when I restarted the car after fueling, it wouldn't work until I tapped the casing. It will some times start working just driving down the road.
I purchased a third unit and installed it Friday when the second unit quit. It didn't work either so I reinstalled the second unit again and tapped it and it worked for the next 500 miles or so. I at first thought I had a problem with the wiring harness but I'm not sure now. Is there another relay other than the one on the control unit that may be mal functioning? I am on the road (about 800 miles from home) and do not have my service manual with me.
AnswerHi Melvin,
That is interesting. I wonder if you might not have a loose connection to the unit's main ground point which is nearby: on the airbag module's mounting bracket. That wire is the black/light green from pin 6 of the 8 pin connector at the head unit and the air bag module is in the same general vicinity but behind the other control units. It may just be a loose attachment at the air bag bracket or a bad solder at the pin 6. Anytime something such a unit shuts down like that and can be restorted by tapping I think of power supply or ground. The voltage supply for the unit is on pin 5 of the same plug so check that pin/wire solder connection, too.
Roland
