For the past few days, I have been troubleshooting possible solutions to my problems. Maybe you could help me out. I would appreciate it...

My A/C clutch & fans do not kick on. The fans do work for engine cooling, but not for the A/C.

I checked the A/C clutch relay (of course fuses) & it checks out fine. If I jump the wire for the clutch it does engage.

I bought a Manifold gauge & hose kit to test for pressure. I tried to jump the High/Low A/C Pressure Switch to engage the clutch & nothing... So I went ahead & engaged the clutch from the relay to test the pressure & it was kinda low. I added a little bit (up around 35 p.s.i. on low the gauge & 200 on the high) & I hoped when I plugged the relay back in it would kick the clutch back on....nope!

I did notice something weird, it would hover at around 35 p.s.i. low/ 200 p.s.i high but then both gauges went up to around 50 p.s.i. low/325 p.s.i. high & I heard a noise from the receiver/dryer area (front passenger side) & it went down back to 30. It would repeat every 3-4 minutes.

It did cool down a little (5 degrees) in the car, but since I jumped the clutch, I didn't want to run it for long.

So, I'm down to the A/C thermostat or the ECM module. I grounded the blu/red wire (while plugged in) on the a/c thermostat plug & the clutch/fans still did not engage. But the other two wires did check out... I am unable to test the ECM due to the "special wire harness" required.

Any idea's, comments or suggestions? THANKS!!

 

Sorry I forgot to mention that I just replaced the radiator fan module. (burnt diode) I'm guessing whtever caused that, is causing my a/c not to work.
I just bought the car & someone jimmy rigged a wire under the hood fuse box to make the fan run all the time.

 

It appears the ECM is not grounding the relay to enable the compressor. Why? It could be a bad AC Diode or other input (overheat?, cooling fans out?,?)causing ECU to deny ground. Do cooling fans come on when you force the compressor to engage? W/O cooling fans system pressures will escalate quickly, so don't run very long w/o cooling fans. The ECT switch B may disable AC when it is closed, however this should cause fans to run all the time if it has fail closed. The fact that AC did not come on when you jumped the Hi/Lo pressure switch suggests that AC diode may be open. Suggest checking this first.

It could be the AC thermostat is defective, but this is less likely than above.

Be sure to flush your hoses when you introduce new R134a to avoid pushing air into your system. Either flush w/ system R134a or from supply to clear air.

good luck

 

Thanks for the info. The fans do not turn on when clutch is engaged. It does however when the car warms up, so I know they work. I will double check the AC diode. Could I send a negative trigger through the A/C thermostat (blu/yel output) & also bypass the pressure switch?

Thanks again!

 

You can check the pressure switch. If you have a charge it should show a dead short. Unlikely to be your problem.

Check the AC diode before trying any more jumpers. I suspect the jumper may have been the source of some of the problems. If AC diode is OK, this leads to the thermostat as most likely in my view.

good luck

 

Thanks for your help. I went over my diagram & re-tested everything. I found my problem, A/c thermostat! I grounded the blu/yel wire & the radiator fan, clutch engaged. (manual said blu/red... ) I added some more freon to 32p.s.i & the air was getting colder!!!! but I noticed something weird.. One vent is cold, next one is hott....?? I checked the valve at the firewall & twisted it all the way closed & now we have ice cold air.. thanks everybody who helped, & provided suggestions..

I do have another big issue on my car (I just bought it)

The Temp gauge says it's running hott... Like 1/8" to red hot! But I will created another thread.. Thanks again Texashonda!

 

Good Work.

The blend valve actuator can be adjusted. There is a detailed adjustment procedure in the 94 Accord manual. If you have a high speed connection try http://www.hondahookup.com/manuals/.

Regarding overheating, I would buy or borrow a IR temp gauge and check the coolant temp on the upper and lower radiator hose connections to the engine. You could have a bad gauge, but a bad thermostat is more likely. Get an OEM thermostat if you have to replace.

good luck