cooling fan wont come on properly

[jessie]

96 Olds 88 LS 3800 K series engine

Replaced radiator (dead spots and can see previous silver seal work) temp sensor and the high and low relays. Still not coming on when gauge gets to the range. Fan works if on auxiliary (unplugged from temp sensor) or hardwired direct. Read tech bulletin on other GM in this timeframe with wire kit for tem gauge...not sure if applies here or what to do...beating head on wall.

[Terry]

Don't remember any tech bulletins for this problem on the Oldsmobile with the 3800 engine- I have worked for Oldsmobile since 1988. This sounds like a possible PCM or wiring problem. The PCM controls the relays. This system can get a little confusing, especially if you have the heavy duty cooling wit5h two fans. The fans circuits go through both relays differently depending on engine temp. You would need to get a wiring diagram and test light and do some testing.

[jessie]

Yep..I have the dual fan set up. Guess I need to find a diagram. I keep hearing people refer to the "switch" for the fan...where is that??

[Terry]

People who dont know much about cars call the temp sensor the "Switch" since that is what triggers the fan ON request.

[jessie]

OK that makes sense. My brother told me only one of the relays was replaced so going to do that too ($20 bucks but have feeling it's a stupid wire issue to be found). Just to verify that I'm right one fan kicks on at 212 and the other should around 226??

[Terry]

yes, go ahead and replace the other relay and see if that fixes it first.
The low speed fan fan comes on about 226 F, the high speed at about 240F.

[Terry]

Did you every find your problem with the cooling fans?

[jessie]

I don't have the toys needed to track down wiring issue. Waiting until payday to get it to a shop to find.... oh the joys of cars.

[jessie]

Finally got it in to a shop. The temperature sensor I purchased wasn't reading correctly... got a different one and works great now. Of course from car sitting for couple months tranny has a whine... time to change fluid and filter grrrr Oh well it is at the recommended mileage for it.