So I've had AC issues lately. First had a bad expansion valve. Fixed that last year, everything worked fine for awhile. Then I noticed a slight freon smell in the car, and the air got warmer and warmer over a period of weeks. Pulled the evaporator core and found dye in the box, so obviously had a leak in the evap core. Bought a new one, installed last week, and the questions start.

Vacuumed system down, added one can of R134A. Neither fan was running. When I started adding the 2nd can, compressor would kick on, but not often, and when it did, it was hard starting and would almost stall the car. Fans still not on. High pressure side was way up, low pressure side was ok. Can started getting warm in my hand, so I shut things down. Had a leak at the high side port after I disconnected gauges, so replaced the valve core.

When I went to pull the evaporator back out, wondering what I missed, I noticed I neglected to plug the fan timer back in.

So, would THAT have caused fans to not come on? I'm thinking the lack of airflow across the condenser caused high pressures, which would explain the compressor bogging down on engagement.

I removed evaporator, blew compressed air through it to make sure I didnt't get a faulty core with some sort of blockage, reinstalled, plugged in fan timer.

Vacuumed system down, turned key on, turned AC on, no fan. I believe there is a pressure switch so the AC fan won't come on until system is pressurized, correct?

I ran jumper wires to the engine cooling fan (driver's side) and it runs fine with 12V applied. I tried jumpering the green plug on the thermostat housing with a paper clip, got nothing. From my understanding when I jumpered those wires, the engine cooling fan should come on. Is that incorrect?

I swapped relays in the underhood fuse box, and both appear to work in the power window spot, so appears relay is good.

Thoughts? I don't want to charge my AC system again until I make sure my cooling fans are working properly.

 

Start with the simplest test to figure out what is going on. Jumping green ECT switch A on the thermostat housing should turn on both fans and didn't happen. The key will need to be in the II position for the fans to turn on with this test. If the fans don't turn on with the key in the II position, use a volt meter on the green wire to ECT A and measure for voltage to the engine block. Repeat the test from ECT A green wire to ECT A black wire.

 

Thanks.

So should there be voltage at the plug? I figured that sensor would ground at a certain temp and connect the two wires.

This is the correct sensor plug, right?

 

Is this a 93 or 94 accord?

 

It’s a 94 LX.

Guess I need to change my sig. My 93 was gone in 2008. Miss that car.

It was a Black coupe 5 speed EX.

Got this 94 LX then with 60k on it. Has around 350k on it now.

 

Ok. Your picture is ECT B that turns on just the radiator fan when the car is off.

ECT A also has a green electrical connector and is on the passenger side of the engine past the distributor. It is very near the air bleeder when you are filling the coolant.

Both ECT sesnors get 12V on one wire and ground on the other wire. When the temperature reaches the set temp (200°F for ECT A and 223°F for ECT B), the switch closes and grounds that 12V to turn on the fan relay(s).

 

Gotcha. So measure for voltage on that plug and don’t try to jump the contacts on the plug.

I do a lot of work on Honda ATV’s, and figured some of the same type switches and wiring would carry over to the cars. I just seldom have any issues with the Accorfs.

 

You can jump the connector and see if the fan turns on. If the fan doesn't turn on, then you can check for voltage.

 

Will try that in the morning. Thank you!

 

Tried the proper plug you pointed me to, and both fans came on.

Apparently having that fan timer unplugged was keeping both fans from working. When I jumped the plug, both fans came on and ran fine.

I also learned from this just how important airflow is for the A/C system. When I tried to charge the system before with fans not running, I got overpressure on the high side, a hard starting compressor that would almost stall the car.

Once I confirmed fans were working, I went ahead and charged the system. Compressor and fans kicked on as soon as I had enough pressure to trigger the switch, and both cans went in without issue. A/C is blowing cold, compressor is having no issues starting and stopping, and fans are working fine now.

HOPEFULLY this won't give me any trouble for several more years. I'm only at 350K now, so just getting broken in.

Thanks for your help @PAhonda !