2manyfuncars

I would like to bypass the ECU control of the main fan in my 1990 6 spd and turn it on at a lower temp. Is there a readily available harness available to do it? I think another way would be to get a new ECU chip, but until I do more mods, I'd rather wait. My car has only two sensors, one for the gauge and one for the Fuel injection control. There is not a separate fan switch like some C4's have. I have a 180 deg switch already but would have to wire it up to the relay somehow.

Thanks for the help

65Z01

So you don't have a fan sw in the left side of the block below #1 & #3 plugs?

I posted a tech article on how to cheaply use the aux fan sw to control both fans.

Let me know more about your fan sw setup. My '88 electrical diagram shows a digital sw into the ECM when only one fan is present.

2manyfuncars

My 1990 only has a temp gauge sensor on the pass side. I know it's the gauge sensor because disconnecting it sends the gauge to low temp. I checked a 1989 conv someone has here and it has a sensor on the pass side and a switch on the dr side. His fan and shroud set up is also different. Mine does not have the front fans. It does have two rear fans - one large and one small. I read somewhere that the radiator and fan set up was changed in 1990. I also put in a Ron Davis Al radiator this weekend. Is there a simple way to wire the relay for the larger of the two fans?

Thanks

Aaron's 87

Spend $200 on chip burning stuff and start with the fan temps. When you really mod the car, you can make your own chip.

h rocks

2Many, call Jegs and get the 185 deg. fan switch that goes into the hole plugged between #1 & #3 cyls. It's $39. You can connect either one or both fans. It's a no brainer and very effective.

2manyfuncars

Now I understand the issue. All I need is the right harness for the switch to connect to the relays.
I already have the switch and I can make a harness.
Thanks for the help.

Togo

hey 2, you can get a wiring harness at mid america, its between 13 and 18 dollars, depending on if it is still on sale this month!