My coolant fan is not working on low speed (?) how do you tell if it the fan or resistor? I am getting power to both wires at the three prong plug. Is there any way to jump the fan to see if it works at all?

 

Start the car and let it sit. You should get hot enough to trip the high-speed temp sensor. If both fans engage at high speed then either your low speed relay is shot or the resistor. There is a sticky thread here with the hows and wheres. I have the resistor bypass in place and have a spare "green" resistor in my car with a harness already soldered on with clips as the greenies do not appear to last as long at the goldies.

 

At which point does the high speed kick in? I had it at 234* yesterday and nothing.

 

Should kick on at 234 so if you hit 235 and the fan does not work than I would then get the fan into a position so that I could jump with a power lead to see if they run. If it runs with the jumper, then you need to check the two relays, one for the low and one for the high. I am thinking there is a switching unit fuse as well. Check out this thread that has the fuse and relays listed.

On another type of car the fans were not working, I jumped as above and they worked fine. I then found one relay and one fuse were bad.

https://www.northamericanmotoring.co...nd-wiring.html

 

When i jump it, use either one of the red leads?

 

So I had to run a jumper from a grounded bolt to the black lead and a power jumper to the bigger red lead and the fan kick on. My guess is the infamous resistor!!
Side note, when it was hot yesterday I had power to both red leads.
Low speed runs through the smaller gauge wire and high speed runs through bigger gauge wire.

 

Pretty sure the resistor does not impact the the high speed.

 

So the previous post I did with the car off. I wanted to check some other thoughts out. Went out started the car, no fan ( expected, not warm enough) turned on max a/c. Fan came on, low speed. Turned off a/c,fan stayed on, temp was at 190*. Turned a/c back on and moments later the high speed fan kicked on. Let run for a minute or two, temp never got above 195*. Turned off a/c again and fan went back to low speed.

 

If the low speed is only coming on with the AC then I am wondering about the relay. Would think the relay has a set of pins for the power and that the circuit closes with either the AC call or a temp sensor call.

 

With a week of checking, I was getting power to the plug but the fan wasnt moving. Tried jumping it a few times with no luck. Replaced the fan this morning with one from rockauto. Now it works as it should.