Installed aftermarket Fan Switch, NOW have problems...please help

[XtremeVette]

Ok, first off, my vette is fine....lol

This is for my brothers 89 Firebird with 5.0 TPI and dual fans. So basically we are still talking a similar animal.

Ok what was done.
New radiator was installed.
New lower fan turn on switch installed in what was thought to be the stock location of the stock fan turn on switch.
The location was on the passenger side and between the last 2 spark plugs.
What happened: the new switch from hypertech did not have the same type of connector so cutting of the wiring and splicing had to be done.
After the new hypertech switch was installed. Temperature guage on the dash did not work at all. NOTHING. Also fans do not come on at all.

I hooked up my scanner and no codes show up and the fans do turn on with the scanner plugged in. Like they should. So, I need help now as Iam not sure what to tell him. He tried going back to stock and resoldered back the wires and stock temperature switch but no luck, still not readout on the dash and no fans turning on.

So please send some help my way and his.
Thanks guys
Jeff

 

[nickyg]

Hi xtremevette. I've owned f-bodies since I was 18, now 48, and I still have my 91 T/A 5.0 TPI. I installed a low temp coolant fan switch from MidAmerica like you did with the hypertech. If your getting no fan activity at all and getting no codes, the problem could be with the fan circuit. First I'd check the fuse box for the 2 fan fuses (fan1, fan2) to see if they're blown. If so replace. If I'm correct, there are 2 relays for the fans. They should be mounted on one side of the radiator. They could be bad. Secondary fan should turn on when you switch on the A/C. Also check the wiring going to each fan. The wire you sliced the new connector for the coolant fan switch- if you ground that wire to chassis, the fan should turn right on. Hint- that's the wire that people use to install a manual fan switch which they run a wire to a switch in the dash and then to ground. For more info on f-bodies, have your son go to thirdgen.org and join the forum. The technical info on that site that you can search is a wealth of knowledge dedicated to 3rd gen f-bodies only. The site works just like this one. Good luck!

 

[elints]

In spite of what GM does the fan switches belong on the inlet side of the radiator and the on setting should be just above the thermo setting and the off 10 to 20 degrees F below. You can measure the engine temp wherever you think GM intended it to be but the fans should be controlled by the radiator inlet temp just like Porsche does it.
Do you still have the old switch? I have a feeling it isn't a switch but the temperature sending unit for the engine.