a/c problems ....help! - Honda Prelude Forum

jgcpn33 · 08-09-2003, 08:51 PM

i've searched through all the a/c threads i could find and couldnt find one like mine.....

Well the clutch on my a/c compressor is not engaging automatically, but it works cause I had my old mechanic from indiana look at it when I was visiting, and he could manually engage it and the compressor would come on......

right away he figured out it was electrical and literally worked on it a couple hours a day for a week and couldnt trace what was causing it.......
i know some people have had problems, with a/c control units, so i got one from a junkyard and that didnt solve the problem...........
i also have a spare ecu and tried that in case something shorted out, but that also didnt work......

*the one thing that could've/probably caused this is, right before it stopped working i cleaned my engine bay......covered up all necessary parts, but not any a/c parts???*

i didnt drive it for a day or two later so i'm not Positive that caused it.....

I'm not too skilled with electrical stuff, but i'm willing to try.......

also i can take back the a/c control unit and credit it to something else at the junkyard which has ALOT of preludes.........

thanks,
jonathan

marcucci · 08-09-2003, 09:36 PM

You will simply have to trace it. Get the factory manual, that will help a lot. There is at least one relay involved in addition to the hi/low pressure limit (safety) switch and the thermostat in the cabin. You will likely need to trace through all of these, looking not only for the presence of 12V but also to make sure that none of the elements in the clutch power circuit are resistive. Anything over a few ohms will prevent the clutch from engaging.

Phamine · 08-10-2003, 08:24 AM

I just did a quick check

To check:

1. Remove winshield fluid waterneck (10mm)
2. Remove the AC relay, it has a white/green wire and Solid Red
3. Check Relay by powering the switched part of the relay(Silver connectors)
4. Use Multimeter to check gold connectors for contiinuity.
5. Check the relay connector for voltage(12V) from white/green and solid red.
6. Jump white/green and red wire from the relay connector - turn on car and see if the compressor clutch engages
7. Disconnect compressor connector by the fan
8. Check for continuity from connector(not connector on compressor) and red wire on relay connector.
9. Check for armanture rotor clearance from the rotor pulley
10. Check thermal protector(it's the Insulated Female side of the connector located on the compressor) for continuity with the compressor side of the connector.
11. Check field coil resistance(male side of the connector you just disconnected) Should be around 3.2 ohms

For me, it turned out the A/C switch on the climate control was at fault. I just banged the area around the switch and it started to work again