Having A Fan Problem: Fans Come On, Temp Stays About 180, Drive Awhile And Dashboard Gauge Jumps To 220 Ish... Check Fans And They Are Off. Drive Awhile More And Temp May Drop As Fans Come On Again. Am I to understand the pcm turns them on off as ect Sensor dicates? Any Help Appreciated! Kris

I am assuming that you have a 180°F thermostat?

To answer your quetsion, it is "Yes."

Low speed fans are commanded on at ~216F, high speed is commanded on ~228F.

Seems like proper operation to me. That'* leaving out the part that any speed above ~40mph they turn off as the airflow should be moving faster than the fans.

Thank You Cheetah. I Thought Perhaps There Was A Temperature Controlled Switch Up By The Fans Controlling Them. And Yes I Do Have A 180 T Stat With One 1/4 in Hole In The Flange. Should There Be More Or Bigger Holes? Bill: Thank You Too. I Figured They Were Not On When They Should Be. I Take It Everything In The Fan Dpt. Is As It Should Be Then? It Seems My Temps Used To Be Steady At Just Below 200. If Every Thing Is Now As It Should Be Is It Desirable And Possible To Keep My Temps Down To At Or Near 180?

You should be able to force the high speed fan to come on by putting a switch on the ground side of the high speed fan relay. The switch will ground the high speed fan relay regardless of engine temperature. To install, run a wire from a ground location to one end of the switch and run another wire from the other end of the switch to the wire going from the High Speed relay to the temperature switch connector. You can splice into the wire at any point. I'm not familiar with the wire colors or relay locations on the Pontiac, but if you have a wiring diagram you should be able to figure it out. Put the switch somewhere in the cab easy to find. Don't forget to turn it off when you kill the engine.

I would not worry about testing the hi speed mode. I have had my car for 4 years, and of that I lived in Georgia for 2 years. Letting the car sit in 100-105°F with the A/C on for a considerable amount of time, the H/* mode never kicked. Those 2 fans do a GOOD job pulling air on low speed. IMO, there is no need to splice anything.

For the holes in the thermostat, depends on what you do with you car and where you live. Use the search feature, you will pull up A LOT of articles on it I looked into doing it, but I live in Alaska and it'* not needed in -19°F as a daytime high

Although, I've not done this yet to my wife'* '97 LeSabre, I've done it to my '95 Saturn, and would not be without it. I placed my switch on the upper dash to the left of the steering wheel. It comes in very handy, particularly when driving through the Los Angeles Freeway traffic, which is basically stop & go.

It'* turned out to be invaluable to me, while my Saturn now has 506,794 miles on it. And I'm the original owner.

I should note, such an installation does not change any of the other computer controlled radiator fan activation inputs.
It is simply an added way the fan can be turned on.

Guys, I Am Weigh Happy 4 Your Input, Really. I Have Everything To Do The Overide Switch This Sunday. That Is With The Help Of Your Very Specific Info! Still I Dont Like Overiding My Pcm. Why Does The Pcm Allow Such A Large Up Swing In Temp Anyway? Minus 19 Dude? Havent You Heard Of Condo Time Shares In FLA ? ha ha . laughing Kris

I should stress, the insertion of a manual switch, simple is an additional & independent way the fan can be activated.
None of the other activating fan controllers is affected, no overridden.
It is simply and additional means by which the fan can be activated, and at a point the driver wants.

Now ya see, to me that really doesn't make sense. by the time the engine coolant temperature reaches ~228F it'* already starting to get to hot for me. In my opinion, the high speed fan should come on at around ~216F.

By the way, Will did an amazing write up in one of my thread on how to install an over ride switch to the pcm. I did it myself and have been using that switch on a regualar basis. Well Mick has anyway.