ok so i bought TPI parts 200-180* fan switch. it works great keeps the car at a "safer" temperature. but my question is what fan is suposed to turn on? before i installed the switch im almost 100% sure it was the drivers side that turned on. but after i installed the switch the passanger side fan turns on.
i always thought that the passenger side fan only turns on when the ac is on and the drivers fan is the primary.
its a 87 GTA 350 TPI dual fans

 

On my 87 GTA....

Passenger side primary...Drivers side secondary.

 

On my 88 Formula, Drivers side Primary and Pass side secondary. Secondary Fan is controlled by the fan switch in the pass side head as well as the A/C Pressure switch.

 

ok so it seems its different for different cars. so if the fan switch between cylinders 6 and 8 control the secondary. what controls the primary?

 

The primary driver's side fan is controlled by the computer, which gets its input from the coolant temp switch in the front of the intake manifold. The passenger side fan is controlled as Zepher said.

And in case someone asks, on a single fan setup, the fan is controlled by the fan switch in the passenger side head. The computer does not control it.

 

Are you sure that on a single fan setup that the fan is controlled by the fan switch in the head? I have a 86 TPI with a single fan and I have no fan switch. The wiring diagram shows the fan relay going into the ECM and to the fan itself with no fan switch at all.

 

Are you sure that on a single fan setup that the fan is controlled by the fan switch in the head? I have a 86 TPI with a single fan and I have no fan switch. The wiring diagram shows the fan relay going into the ECM and to the fan itself with no fan switch at all.

 

ok now i under stand, so really the only way to make the primary fan come on lower would be to go into the computer and change the temp.

but i guess if i wanted the primary fan to work first again i could just unplug the secondary fan and plug it into the primary and vice versa. assuming the wires reach. thanks for the help guys!!

 

I'm mostly familiar with the later 88-92 setups, so if an '87 and earlier setup is different than I described, than I apologize.

 

Yeah the fan on the pre 88 TPI single fan cars are operated by the computer. No worries.

 

My 87 GTA 350/TPI has dual fans & my FSM for it shows dual fans, so it hasn't just been swapped.The dual fans are original.

 

You nailed it. Passenger fan = secondary fan = fan switch or A/C pressure.

Driver fan = primary fan = computer chip.

Hypertech sells their chips to turn the driver fan on early and they sell the fan switches to turn the passenger fan on early.

You'll really like the 200/185 fan switch. Cool enough, but not draining the electrical system running them all the time either. I'd say it's perfect really.

 

hi i have a major problem my car is running funny. it loose power and shakes badly after a few minutes. i have had it a few shops and after 800 dollars same problem, went to a local dealership and they said i had a dead #8 cylinder, its running hot and my fans not comming on any more even with the ac on.

 

yeah it is nice now to be able to drive and not have to worry about the hot temperetures. and if it does get higher then the "primary fan can come on at its normal temp and save it.


all good: does it give u these issues after u start driving it or right away?