Could some one please clarify for me which switch does what? The fans are not kicking on when they should.
Both fans run with AC on, coolant has been flushed, New thermostat, no visible leaks or coolant loss, Radiator looks fine.
Fan used to run awhile after I shut off the car. A couple times it has reached near the red mark on the temp gage while driving but no fan action. After it started doing that, I did a second coolant flush to make sure I got all the gunk out (there was a lot the first time.) So in the process I'm waiting for fans to kick on, but they never did, even after 40 min but it also never read hot. I've let it sit running in the driveway with the radiator cap off 20 to 30 min- there's no splattering, it doesn't pass the mid mark on the gage, and the fans don't turn on.
Maybe its clogged up with junk some where still or some sensor is no longer doing its job?

 

What makes you think the fans should engage when the temperature gauge shows the engine temperature is in the normal range?

 

With the ignition on, if the coolant temperature at Fan Switch A is above 194 degrees F, the switch contacts should close and a ground signal is sent to trigger both fans to turn on. -- You can use a small paper clip or wire to jump the wire harness connector side and then turn the ignition on, to see if both fans run. If they do run and the car overheats without the fans turning on, then it may be an issue with Fan Switch A (aka coolant temperature switch A).

After the car's been on, and with the ignition off, if the coolant temperature at Fan Switch B is above 226 degrees F, the switch contacts should close and a ground signal is sent to the fan timer, which should trigger the radiator fan to run for a few minutes.

 

If thermostat installed was < 194F rated, the fans may rarely turn on depending on ambient air temp and load.

good luck

 

I figured I would see it the computer wanted to tell me any thing before I got started. I'm not getting any blinks, just a solid check engine light. Faulty ecu?
I'm off to check those switches now,
Thank You!!

 

If service check connector was shorted and solid D4 or sport light, then no codes are stored.

good luck

 

Fans run with switch A jumped. Would a bad A cause B not to work for some reason?

 

No, a bad fan switch A would not cause fan switch B not to work. They are different temperature and independent switches.

 

I am missing something and it is driving me crazy! I replaced both switches, A and B. Refilled the coolant with the bleeder bolt open until a bubble free stream(heat on, not air). I started the car and it ran about 20 min, this time quite a bit of air as well as some coolant burped out of the radiator, the temp gage read 3/4 way to the red, the fans did not kick on-I shut the car off-still no fans. I immediately put the key back in, turned on the AC and let the fans run a couple min.
The thermostat is a fail safe, 180 F. As it was running I felt both hoses, upper one was hot lower one warm.
What could I be missing? I've been upside down with other similar issues. When I first got the car I had to replace one of the fan motors, the two relays that I know of (one in fuse box and one mounted on the side) both of which I have switched with their twins to ensure they are working. The ECU and thermo sending switch were also replaced because they were melted. It dose seem odd (to me) that I'm not getting any codes either.
I appreciate any advice.

 

It's possible you have a faulty temp gauge. With a 180F thermostat, the fans are unlikely to ever come on (194F switch closure). So no fan action is consistent w/ hardware installed.

However a faulty temp gauge is unusual. If you have an Infrared temp gauge (Harbor Freight for $20) you can check the temperature of the thermostat housing and upper radiator hose fitting (engine side) for confirmation of bad temp gauge.

Temp gauge is underneath distributor, a single red wire connection.

Hose temp difference (upper hot/lower warm) is normal for operating system.

The only code for cooling system is code 6 (coolant temp sensor). I'm unsure whether the ECM detects an "out-of-limit" condition or only a short/open condition. Shop manual has a calibration chart that says resistance should be 200-400 ohms at operating temperature.

good luck