Cooling issue, need electrical guys

I've had a cooling issue for 3 years now. I installed a manual high speed switch on it as a temporary band-aid. Now I want it really fixed. And before you suggest it, yes, I've spent hours reading the forums about this.

Symptoms:
1) Gets way too hot at idle or around town driving.
2) Highway driving is just fine, nice and cool.
3) Fan doesn't kick on, at all. At temps. I've read up to 217 degrees without seeing the low fan kick on.
4) Using a code reader, the system cycles the low speed and high speed fans fine.

Attempted fixes:
1) 180 degree stat.
2) Huge alum. radiator
3) New rad. cap.
4) ECT sensor replaced.
5) High speed manual switch (works, but sick of it)
6) System burped of air in the lines.

So given all that: What is up with the fan not coming on? The ECT is brand new. The manual switch fires up the fan just fine. And the ECU diagnostics cycle through low and high speeds while pulling codes.

Thanks!

HISSIN50 said:

Did you post a thread over on the Corral? If not, check over there because I think I just replied to a similar thread over there - maybe you can compare notes with that guy.

Your rad is up to the task if it cools at speed.

With your new radiator, is the fan shrouded close to the radiator (no big air gaps between the fan shroud and radiator)?

Do you have a spare CCRM to swap in? Does Pin 14 show 12 volts at ~210*F? This would tell you if the relay is getting the key to energize low speed.

Are all fuses and relays ok? Is the fan connector burned up? During the CEL test, the motor is likely not super hot. A bad fan motor will increase draw (resistance) when it is hotter.

Good luck.

Click to expand...

I actually do not have the fan shroud even on, but keep in mind it cools fine when I kick on the fan manually and of course on it's own on the highway. The issue simply seems to be the fan not coming on by itself. I don't have a spare CCRM, what do those run pricewise? I will check pin 14 and the fuses. Which relays would I check and how? The fan connector probably isn't burned up since I can kick on the fan manually. I tested the fan motor via CEL test right after driving it home, so it was as hot as it gets. Especially since I drove the last 5 minutes with the fan on (again, manually).

No, that wasn't me on the corral but I would like to see that forum if you have the link! Thanks!