Radiator Fan Issues

IshbOO · Post by **IshbOO** » Sat Jul 31, 2010 12:16 am

Alright, trying to work on my DD teg the past few days.

It has this issue with the Radiator Fan.

The fan will not come on when the engine is hot. When I click the AC on, then Both the Radiator fan, and the condesner fan come on.

This is the only way I can drive around right now, is with the AC on, or my rad might boil over.

I checked all the fuses, seem fine. So I did a little reading and decided to do this.
I decided to change this engine temperature control switch.

#14 on this picture
(PICTURE IN 4th post down or so)

It still does not seem to come on, unless I flip the AC on.

Anyone know what I should check next? maybe a relay or something?

Gunmetal Si · Post by **Gunmetal Si** » Sat Jul 31, 2010 1:06 am

someone has it wired funky

Lynxs1981 · Post by **Lynxs1981** » Sat Jul 31, 2010 2:39 am

Does your gauge read hot and the fan still doesn't come on? If so, you might want to check the temp sender for the gauge(#11). It might be bad, and the engine is not really that hot. Also #13 is a sensor for the ECU, I think it is also related to fan activity. Are you any good with a multimeter?

Have you done a coolant service recently?

99SilverCX · Post by **99SilverCX** » Sat Jul 31, 2010 3:09 am

Gunmetal Si;240288 wrote:someone has it wired funky

that's what I'm thinking too, when you short out the 2 pins on the temp switch the fan is supposed to automatically come on, I know this because I've been driving like that all summer since my fan switch went out

Does the car have OEM radiator and fans? or aftermarket?

IshbOO · Post by **IshbOO** » Sat Jul 31, 2010 6:10 pm

Here is a little more info on the vehicle and situation.

Everything is OEM. We put the engine in not too long ago, all the coolant should still be pretty new.

The engine used to over heat(the gauge would go to hot) once we first put the engine in, only If sitting idle, didn't ever find out why, probably this same issue but it seemed to have went away on its own or I figured out the fan wasn't comming on. Now the temp gauge seems to go where it is supposed to weather I have the fans off or on. I haven't seen it go up for a really long time.

I can tell the RAD is hot, very hot. You can also smell it if I dont turn the fans on.

This is a 1994 obd1 b18b in a 1997 obd2a GSR chassis. Im using the 1994 ODB1 engine harness, and I'm using a 1997 OBD2a P75 from an LS.
The engine I'm pretty sure has a new timing belt and waterpump as well.

I dont see that there would be any issues with the wiring anywhere. It must be some sensor or something.

Sometimes I get a CEL, but I know what it is and how to fix it, and it has nothing to do with the fans.

And I'm not to good with a meter, but I use one here and there.

I changed #14.

#15 is a Water Temp Sensor and #13 is THERMO UNIT (DENSO) I think. Here is the correct picture for My Engine, sorry for any confusion.

IshbOO · Post by **IshbOO** » Tue Aug 03, 2010 1:07 am

Problem was resolved. Thanks for all of your input. Ended up being the switch after all. I guess I just never tested how hot the coolant actually got. It would idle around 173 farhenheit. the fan supposed to kick on at 199. We ran the car down the highway a few times, came back tested the coolant, it was at 201 farhenheit and no fans. We then idled the car for a minute, sure enough both fans kicked on with the AC off.

Guess my testing wasn't the brightest, but we figured it out. On to the CEL and then a good detail cleaning. Then the car will be forsale most likely.

Thanks again STLH! everyone seems to help out with the knowledge here alot. I learned alot about the wiring of RAD fans. and coolant system.