86 ta 305 4bbl..........
fan comes on when ac is turned on only...wiring was pretty screwed up from last guy...changed fan relay,temp sensor on water neck..
troubleshot from 86 pont ta manual, still wont turn on,car overheats.
temp guage wont work either.....redlines when car starts,then drops below 100 degrees and wont budge...
any ideas? going nuts!!!!!!!

 

cant help you there, but the guys over in the cooling or electronics section might.

 

Yep wrong forum, should be in cooling.

Sounds like a fan temp switch is either burnt up on the passenger head and the temp sensor on the driver side head is not connected either. I melted both off my car, gotta post pics.

 

There is a temperature sending unit on the driver side of the block just below the heads. I broke this off putting my headers on, car did the same thing. Check this out. You can get the sending unit at any parts store.. it is actually called an "electric fan switch".

 

I had the exact problem on my 89 RS. There are three temp sensors on the engine. The one on/ next to the water neck is for the coolant temp gauge. So by replacing that you did nothing. There is a sensor on the passenger side of the engine between the #5 cylinder and #7 cylinder. It screws into the block. That is the sensor that controlls when the electric fan comes on. That is the one you need to replace. There is also a engine temp sensor ont he driver side of the engine bewteen the #2 and #4 cylinders, that i think is for engine temp. I think is is strictly for the ECM to use. What i did was went to jegs and picked up the new temp censor and relay and harness, to controll the fan. I also went with an afternmarket fan that mounts directly to the radiatior to get a lot more air flowing through it. Now with the fan switch and relay and wires from jegs it is everything you need including connectors. And the best part is that you can get either kit to make the fan come on earlier. Because GM engineered these cars to Run HOT. So go with the lower temp fan switch and wiring kit. If you want more exact details and things like that PM me and i will give you all the help i can.

 

THANKS FOR THE ADVICE.........I BAUGHT THE PONTIAC SERICE MANUAL FOR MY CAR LAST WEEK.....WHAT A BIG HELP ! THE WIRING HARNESS WAS HACKED UP BY THE LAST OWNER.....GUESS HE TRIED TO FIX IT HIMSELF WITH NO LUCK.ANYHOW,THE WIRING DIAGRAM HELPED, THE TERMINALS WERE GONE ON BOTH SWITCHES.THE DRIVER SIDE SWITCH IS FOR THE TEMP. GUAGE.GOT THAT WORKING TEMPORARILY BY STRIPPING WIRE & WRAPPING AROUND THE SWITCH. THE FAN SWITCH IS ALSO MISSING THE CONNECTOR.IM GONNA TRY JUNKYARD FIRST ,OR ELSE IM GOING TO TRY THE DEALER.... I CANT GET THEM AT AN AUTOPARTS STORE....ALREADY TRIED.IM GONNA GET A NEW FAN & SWITCH KIT LIKE YOU EVENTUALLY,I JUST WANNA SEE HER WORK FIRST.HOW MUCH DID THE SETUP COST YOU?
THANKS AGAIN FOR REPLYING.