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*update* it was indeed a faulty heater control unit under the radio. Used a credit at pull a part and now she is fixed.**
Ok. I'm about to pull my hair out. 96-98 civic (forgot year) compressor won't kick on. All fuses and relays are good. The problem is almost certainly wiring.
This is the schematic.
The green slash indicates a cUT in the blu/red wire. Someone had intentionally cut and stripped back the wires. Thought I had it licked...nope. if ground is applied to the blu/red wire the compressor will kick on.
Most of the stuff I read said the check the ecu out. So I put ground to both the ecu terminals that control ac and the both caused the compressor to kick on. Swapped the ecu out...same results.
If I follow the wiring diagram I see that inside the heater control panel the blu/red wire enters and hits a switch to ground. What are the odds I have a bad heater control panel?
Oh and before grounding blu/red shows like 5 volts. Blu/white shows 13
Last edited by Hatecity24; 08-06-2016 at 04:35 PM.
Reason: Fixed the problem
Ok. I'm about to pull my hair out. 96-98 civic (forgot year) compressor won't kick on. All fuses and relays are good. The problem is almost certainly wiring.
The green slash indicates a cUT in the blu/red wire. Someone had intentionally cut and stripped back the wires. Thought I had it licked...nope. if ground is applied to the blu/red wire the compressor will kick on.
Most of the stuff I read said the check the ecu out. So I put ground to both the ecu terminals that control ac and the both caused the compressor to kick on. Swapped the ecu out...same results.
If I follow the wiring diagram I see that inside the heater control panel the blu/red wire enters and hits a switch to ground. What are the odds I have a bad heater control panel?
Originally Posted by Hatecity24
Oh and before grounding blu/red shows like 5 volts. Blu/white shows 13
If I understand the tests you did, they were telling you that the ECU is fine. Did you properly splice the cut wire?
What's the exact problem? Does the fan or compressor or both fail to work when you press the button?
Best first step is to remove the drivers side headlight
Ok check for voltage to the ac compressor, the red wire. If no voltage is present then jump the switch on the dryer and test for voltage. If you are still not receiving 12 volts check thr connector next to the condensor fan behind the drivers side headlight
With the button? If so, the heater control panel and thermostat are fine.
but the compressor itself will not.
Did you test the pressure switch? Is there any refrigerant in the system?
Originally Posted by chrysler kid
Best first step is to remove the drivers side headlight
Ok check for voltage to the ac compressor, the red wire. If no voltage is present then jump the switch on the dryer and test for voltage. If you are still not receiving 12 volts check thr connector next to the condensor fan behind the drivers side headlight
Jumped the pressure switch and the thermostat and still no go. I do not have power at compressor. I can manually run power and it kicks on. Basically my question is...what makes the blue/red go from 5 volts to ground? Is that a switch in the heater control panel?
The control panel grounds the wire to pull the voltage down. If the thermostat finds the temperature is warm, the ground passes to the fan relay and starts the fan. If the pressure switch is closed, the ECU sees the ground and will turn the compressor relay on, if the engine rpm is OK. If the engine is idling abnormally slow, the ECU keeps the compressor off to avoid stalling.
Jumped the pressure switch and the thermostat and still no go. I do not have power at compressor. I can manually run power and it kicks on. Basically my question is...what makes the blue/red go from 5 volts to ground? Is that a switch in the heater control panel?
If the signal is reaching the ECU, the engine will idle up slightly just after the button is pressed. About 1/2 second later the ECU turns the relay on.
. Everything green was ok. The red (the original broken wire blu/red) did not have continuity from the ecu to the pressure switch. So I wired up a new wire real quick (and jumped the pressure switch connector) and did show continuity. Cranked it, hit the ac button........ nothing. Hit the ac button again to turn it off....and click the compressor comes on. So I hop out to check it out befuddled. I then realize that the relay is still popped out from me testing earlier. Pop it back in expecting everything to be a-ok. Compressor kicks off, hop in the car and hit the ac button to turn it back on and bask in my victory....nothing.Nope. just my luck....I still have no ac. Either with the button pressed or not. Oh....my... god. Lol
07-28-2016, 01:53 PM
