QuestionHi Roland. I'm trying to figure out why the cooling fan on my 88 LeBaron 2.2 Turbo A/C won't come on automatically. I've been working on the car for a couple weeks (radiator failed, coolant in transmission, ATF in radiator). I'm stuck on the fan problem now. I've been working on it for some time and have spent several hours searching the net.
The fan motor is ok. The relay is OK. The wire from the relay to the fan is OK. I took the cover off the relay and activated it by hand and the fan ran fine. When the car's running and I disconnect the plug from the temperature sensor the fan comes on.
I removed the coolant temperature sensor and tested the resistance. At room temp, it was around 9,000 Ohms. In a pan of near-boiling water it was about 800 Ohms. I can't find specs for what the resistance should be, but it seems like it's working. Now what?
I would mention that a few days ago the fan did cycle on and off a couple times when the engine temp gauge was mid-range. I thought that whatever the problem might have been, I had fixed it.
All the testing has been done with the car parked. I've had the battery disconnected many times in the process of working on it. Not sure what other clues I can give you. But I sure appreciate your help.
While you're here, I've been going nuts trying to determine the correct ATF for the 88 transaxle, which I assume is an A413. Dipstick says Dexron II. But I read elsewhere that Dexron is death. So I put in ATF+4. Then I read that +4 has been shown to work fine, but will degrade seals in some transaxles, and that +3 should be used. I don't know who to believe.
Thanks so much for your service.
Mike in CA
I'm guessing it's something between the CTS and the relay.
AnswerHi Mike,
Those resistance are fine: spec is 7,000 to 13,000 at 70F,
700 to 1,000 at 200F.
With the new radiator and fresh coolant, etc. I suspect that the coolant temp is not getting high enough to initiate the fan. It sounds like the circuit is o.k. if the fan comes on when you unplug the sensor or if you select the A.C. Wait till the warm weather returns and I think you will find that it is ok.
It will not come until the coolant reaches 230F and you are moving at 40 mph or higher. Below 40 mph it comes on at 210F. Also, it should always come on when you turn on the air conditioning or the defrost mode is selected, regardless of coolant temp. You could try covering up the front of the radiator to block the air flow and to drive up the coolant temp; then observe the fan to come on. My '89's fan seldom comes on except when A.C. or defrost is selected.
On the A413 the recommendation when it was built in the 80's is Chrysler 7176 also called ATF Plus. Dexron II only to be used if 7176 unavailable. A '98 Chrysler manual shows the similar non-electronic 3-speed trans (31H) is recommeded to use 7176 also known then as ATF +3. I think this is not as significant as issue as for those who have the electronic transaxles, but still try to use the 7176 (ATF +3) in yours.
Roland
