Can anybody tell me where the fan relay is located? Switch-point for mine has always been almost exactly in the middle of the gauge, now it's not switching on but will go on when the ac button is pushed...going to replace the relay first, just need to know where to start looking.
Thanks,
Tim

 

it's in the underhood junction box. The top cover of the box has the layout imprinted on the inside of the lid.

However, if the fan comes on when the a/c is engaged I'd be more inclined to suspect an ECTS sensor/connector/wiring issue than the relay. Faulty temp info derived from a bad ects reading (likely too cold) would have the end result of not telling the PCM it's time to kick in the fan since it doesn't think the engine's hot enough

 

Thanks, Derf...you may be right, I have noticed the temp gauge acting slightly (tiny but discernible notching of the needle back and forth at any temp reading) sketchy...going to replace the relay first, then move on to the ECTS and pigtail if that has no effect...it's a '99, so chances are good I'll be replacing all of the replaceable electrical components in the next couple of years anyway.
Need to keep this puppy running since it has become a valuable necessity where my daughter and Grandson are concerned, for when their junk cars break down and they need to get to work...thanks for the info, this forum delivers like crazy!

 

Ok, decided to replace the ECTS first after all...O'Reilly here in Manteca had the ETCS but not the pigtail/connector, so I'm just starting with the sensor...can anybody tell me where the thing is on the dohc 1.9? A cursory inspection did not clue me in at all...maybe I'm just blind...

 

stand near driver's side fender. Find cylinder head. Look down. It is a two wire device sticking out of the head. It has a squeeze connector on it.

Connector is dealer only and can be sourced from any GM dealer.
GM ECTS's are also preferred. $40 give or take for the pair.

Corrosion on the connector will hose the reading. I would replace the connector as well and be done with it indefinitely.

 

Yup, that's the plan...I also just realized that daughter and grandson somehow are running 100% water in the system, and that may be a part of the bigger picture issue here...she was complaining about having to keep adding water to the overflow and of seeing boiling fluid in the overflow...I know I had to give my credit card number over the phone to a mechanic in Reno Nv when the radiator tank developed a crack last year...going to have to drain the system and re-fill with 50/50 and go from there...

 

In this picture look just above and slightly to the right of the dipstick.

 

Got it, thanks Howard...mine's a dohc, looks like it's a little bit more covered up with the air intake, etc...that's a great pic!

 

Even on the DOHC, it's still pretty much in the same place.

 

Is Teflon tape a must for this application? I seem to recall reading here that it is...