weinerschizel

One of my buddies thinks I may have a shot electric fan motor. Just wondering if these things go out like 1/2 way ever, or if they just don't plane work when they go out.

Thanks!

OBE1 95Z28

Easy to troubleshoot, disconnect the harness and apply 12V directly to the fan connector.

weinerschizel

Already did that. Fans run perfectly when 12v directly supplied. Here is the scoup.

The PCM will not automatically engage the fans once engine reaches temp. I checked all connections; PCM to temp sensor, PCM to relay box, relay box to fans. They are in order. Fan motors run when 12v directly supplied. Also brand new temp sensor, plus logging data on PCM shows temp sensor reading correctly.

One of my friends had a theory that my fan shorted in a funky way. He thinks it may possibly now be drawing too much current for the system to power. That if I buy new fans this may fix my problem. What are your thoughts?

Thanks for the help!

teke184

how bout the relays that control the fans?

shoebox

Did the scanner data also tell you if the fans were even commanded on? It should have. Do the fans come on when the a/c is turned on?

A dying fan motor could run slow and pull excess current or a motor can be just dead. Yours run when directly powered, so probably not a fan problem.

weinerschizel

Fans do not enguage period. Not when the A/C is on, not when the ALDL port is shorted, I couldn't even get the fan switch mod to work (could have been doing it wrong though). I did reprogram the computer to turn both fans on at -30 degrees Celcius to diagnose this. However, they have yet to turn on. I'll have to double check the scanner data to see that they are engauging. That is a good thought. In the past I had checked this and it said they were on (but they were never running). But I haven't looked at it since making a few checks/adjustments.

Thanks for the help!

tom2

Sure sounds like a relay problem to me, especially with DL shunted and no fan. Relay box under the hood, or maybe a fusible link is blown.

weinerschizel

I have checked the fuses. They are good. Upon scanning PCM it says fans are both on (I programmed fans to turn on at -30 degree C).


I checked both relays in my fog light circuit where they work perfectly. Is it possible I have a poor relay which works with fog lights but not with fans???? If I unplug the relays PCM registers a Fan circuit fault.

Thanks for the help guys. It's gone completely mad if you ask me.

shoebox

See if you are getting a ground on the blue and/or green relay control wires from the PCM when they are commanded on. If not, the wiring to that point from the PCM has a problem or you PCM does. Fan wiring and PCM control wiring can be found on my Tech Page.