baldwintpenguin

Hopefully someone has came across this before...when my fans kick onto high my front left one will not come on. If I turn on the A/C however it will. It is not recieving command to relay number one (i think its number one that powers i dont have the schematic with me atm) however when I kick on my A/C it recieves command....anyone ever encountered this? I have two GM MasterTechs stumped

gun5l1ng3r

Why are your fans kicking onto high? They only do that when the car starts to overheat at like 230*F.

Are you using a manual fan switch and having trouble getting the fans to come on the low setting? With my low fans on all the time (manual switch) my car never goes above 185(with my 1998 working gauge).

baldwintpenguin

My car stayed at a constant 185 for months then one day i got in and drove to school and by the time i got to school it was over getting much hotter than it should 225+ I hooked upa Genysis to make sure my gauge was correct and it was. Why would the temp raise all of a sudden?

Old Geezer

iTrader: (3)

Advanced tech??

Steve Bryant

iTrader: (1)

baldwintpenguin,
If you'll send me a PM with your question I'll be glad to help you troubleshoot your overheating problem (to the best of my ability from far away). I'm an electrical engineer and I used to be a diesel truck mechanic so I've done a lot of this sort of thing.

Chuck, AKA "Old Geezer," raises a very valid point. This forum is supposed to be about advanced topics (see https://ls1tech.com/forums/showthread.php?t=396223). Hopefully more folks will take the time to understand what this forum is about and the moderators will take the time to relocate threads to more appropriate venues.

Steve

Zitty'sZ

iTrader: (29)

My car does the exact same thing. I had just finished installing my slp fan switch when I noticed what was going on. If you find out what is causing this, please post the cure.

Steve Bryant

iTrader: (1)

baldwintpenguin,
I don't know what kind of vehicle you have nor do I have the wiring diagram. However, since the second fan operates when the A/C is on, that tells me that fan 2 works, the relay works and the powertrain control module (PCM) circuit for Fan 2 works. This is all goodness.

The way the fan operation is programmed by the "flash" of the PCM controls when Fan 2 comes on. I randomly chose a 2000 Camaro with a four speed automatic and opened that file in EFILive/FlashScan (see below). In this example, fans 1 & 2 are activated at different temperatures (even without the AC operating). Then when the A/C is operating, different parameters control the two fans. There may be nothing wrong, but it may be programmed in a way that is not to your liking. Alternately, the programming "flash" may be incorrect.

I hope that this helps as a starting point.

All my best,

Steve

baldwintpenguin

So after messing with it more the car will get up to 228 degrees then kick my front right fan onto high and cool it back down to 214, sit awhile at 214 then bounce back and fourth. Both fans do not come on low or high, however when my A/C is on both fans will come on high and come on low. My question now is, is it worth wasting more time on it..should I even worry about it if its sitting at 214 degrees mostly? (I hooked up a Genysis so I know hte 214s fairly accurate). Is there anything I can do to fix this and help performance (I mean by taking some small amount of load off the engine)?

Thanks for any more input