Cooling System Puzzle...

[ksmike]

Been puzzled over a 93 Pontiac Sunbird LE with a 2.0 liter.

It all started with overheating and I noticed the radiator fan wasn't kicking in. So I checked the relay and it was fine and clicking properly. So I then hotwired the fan motor and it wasn't working... I replaced it.

The fan still wouldn't kick in. Since I had recently changed the thermostat after replacing the heater core recently I decided to check the thermostat and it is opening properly.

The next step was the temperature sensor. I just replaced it and the fan still doesn't kick in. And worse, now the temperature gauge, which was working fine before, now shoots up to the top as soon as you engage the ignition and the engine is cold.

Does anyone have the answer to this puzzle? I can only hope!

Thanks in advance for any help!

 

[Steelcity]

Perhaps the temp sensor is for a idiot light and not for a gauge type ??? As far as the fan goes are you getting voltage out at the fan ? Check your grounds

 

[melsg5]

did you retest the replacement fan?

 

[ksmike]

Thanks for the input...

The temp sensor was an exact replacement part. Same three-pronged connector and everything. I put the old sensor back in and the temp
gauge is working fine again.

I hot-wired the old cooling fan and it didn't work, but not the new one before installing. What are the odds the new one is shorted? Not likely.

Could it be a computer unit problem? The relay is working properly when I tested it.

The puzzle continues...

______________________________

 

[DanSavage]

Start with pin 1(red wire) of the cooling fan relay, should see 12v. Check pin 4(black/red wire) for continuity to ground should read near 0 ohms. Check pin 5(Brown/white wire) for 12v with ignition on. Pin 1 fusible link on starter. Pin 5 Heater- A/c fuse.