Is it OK to shunt the green/white wire from the PCM to ground, or could this damage the PCM?
pleasedodgevan, do you have experience with doing this on another vehicle? I don’t mind disconnecting the wire from the PCM if that is what is necessary, but would rather having the PCM control the fan as designed.
I doubt that you would need to transfer the chip to a new unit but I can’t say that for sure.
You should be able to have your unit repaired or you can purchase another one. Here is a link that should help you.
Did you miss my first post here? It is up four postings from here.
Experience, oh yah. 83 Camry. When I unplugged the connection from the temperature switch, I noticed that the fan would come on. The system worked but the temp went too high while driving in hot towns to the North or South. I was on the coldest part of the Ca. Central Coast, but the cities nearby were hotter. I can’t remember if smog testing was done after I “fixed it” or not. Nobody should have noticed it. Even the smog guy might not question it. I installed the switch upside down so that the up position would operate the fan. I only had to switch to the up position when driving slowly in hot places. Your situation is slightly different. My experience probably isn’t what you needed. Sorry about the smog testing possibilities.
No, I did not miss it; I read it. But as already stated prior to your post, the fan runs when the relay is jumpered, and the relay works and the fan runs when the relay closes. That was not the question, the question is how to get it to funtion properly, when required by the engine temperature.
And if I’m going to perminately put in a switch to connect the geen wire with white strip to ground and forget the PCM for that function, what happens to the PCM if that lead is shorted to ground? Should I cut the wire first? But why cut it if the PCM can be corrected to control the relay when it is supposed to?
Of course I can get the fan to run! The question is how to ge the fan “running properly”.
Please give me some more suggestions as I still don’t have a good solution.
Thank you Cougar!
That is more help than the part stores have been giving me.
I’ll check that website out!
Still wondering if the PCM would work if I had computer access to resetting something and had the right instructions…
So that means you shunted the PCM? Did the PCM occasionally still turn on the fan if the switch was not in the closed position? Any indication of possible damage to the PCM?
Was the wire color coding on a Toyota the same as on a Chevy? Does that have anything to do with standardization of the programing and code interface?
If you want to add a manually switched lead to ground on the relay control lead that isn’t a problem and you don’t have to cut the lead from the PCM.
If there is something going on in the PCM it isn’t something you can reset. It is damaged internally. If you are sure that the coolant sensor is providing the correct voltage to the PCM that calls for the fan to be turned on and the fan isn’t running then the PCM is bad.