Help! Radiator fan not coming on?

[docjohnson]

I have a 1988 corvette, 2 years ago the radiator over heated and now nothing but problems. Changes the water pump, changed the radiator, changed the relay for the fan and the fan motor but for some reason the fan will not kick on? Checked all fusses and all wiring changed all components for the radiator fan but to no prevail. I gave my car a radiator flush, and still the fan does not kick on. I let the car heat up to about 230 degrees and no fan. Any suggestions would be appreciated.

 

[gmjunkie]

I have a 1988 corvette, 2 years ago the radiator over heated and now nothing but problems. Changes the water pump, changed the radiator, changed the relay for the fan and the fan motor but for some reason the fan will not kick on? Checked all fusses and all wiring changed all components for the radiator fan but to no prevail. I gave my car a radiator flush, and still the fan does not kick on. I let the car heat up to about 230 degrees and no fan. Any suggestions would be appreciated.

Yeah,Let it warm up more,Some early 1988's cooling fan/s won't kick on till it reaches 235*-236* or with the AC running below 55 MPH!

If it still don't, You may have a grounding or ECM problem!

 

[docjohnson]

Does the fan actually work? (as in have you put battery power direct to the fan? )
Do you have full time power at the fan relay?

Yes the fan works, I just put a new motor in it as well. The fan use to kick on when the car reached 209 degrees and would cool down to about 179. We did the direct power to the fan and it turned, wondering if it may be a wiring problem... No idea if I have full time power at the fan relay though.

 

[docjohnson]

Yeah,Let it warm up more,Some early 1988's cooling fan/s won't kick on till it reaches 235*-236* or with the AC running below 55 MPH!

If it still don't, You may have a grounding or ECM problem!

How do I test for the grounding, and what does ECM stand for?
Thank you.

 

[John Robinson]

ECM Engine Control Module (It's the computer or brains for everything that happens to make the car run)

The grounds are the lifeblood of the whole car. Unlike in the past were you would check the value of the power going to a sensor or switch the ECM checks the power going to ground. Bad ground no signal to ECM it gets confused. With that in mind if the sensor that it uses to determine the coolant temp. does not have a good ground the ECM says no signal still not hot enough to turn on the fan. So as Junk said you need to clean all the grounds to be sure they are sending signal to the ECM

Here is were most of the grounds are located on the car. You might as well clean all the grounds from the windsheld forward. Be sure to get the one on the bell housing.

I have a question about the water pump. When you put the new one in did it come with a new temp sensor or did you put the old one back in? The reason for the question is if you changed the sensor then you really can not compare the temp before and after because you may have had a bad sensor that was giving a low reading. The new sensor could actually be telling the true temp that you have had all along. Check some of the resent post here about running temp. From what little you have said about the running temp of your clar it sounds normal.