has anyone figured out what fan switch it is that all the catalogs advertise to turn on your fans earlier? i mean that you can get at your local parts store? and has anyone posted a wiring diagram to install the same? and does it affect your system when ecm tells fan to turn on? i mean the primary fan. i cant see sending away and waiting if we can do this using our local parts dealers and a few feet of wire. anyone????

 

I believe you can just use a toggle switch and wire one side to ground the other to relay trigger.Have you searched the archives.There must be a ton of info on this one. The search tab is on the left side of screen,But i'm sure someone here will step in and set us straight on this one. Good Luck!! :cheers:

 

Here is some info for you:
GM P# 3053190 ON @ 203'F OFF a few degree's colder It fits in the Cyl head P# 12102621 $8 is the mating connector.

MidAmerica P# 17715 ON at 200'F OFF @ 185'F: Stamp# TOD 619710 805 Original ON @ 222'F Stamp# TOD 210310 649 3/8"x18 NPT

There are generic sensor that will do the same, but most parts guys are just button pushers on the PC. If you can find an ol time parts guy or counter, ask to take a look thru there elec. sensor catalog. i.e. Something like GP parts. For starters, you can try the fan switch for the 87. It is the 222'F sensor listed above.

Wiring it is not difficult. The sensor controls the fan relay coil. Typically on the side of the radiator, or firewall. i.e. Don't go directly to the fan. One side of the coil will be hot w/ the key in the ON position. The other side will go to the ECM. This is the side you wanna splice the sensor line to. i.e. The sensor switches to GND. The details depends on your year. Don't forget an inline fuse.

If you really need to look at a book, Pine's in Nashua still uses catalogs.

 

let me clarify! i meant a thermo switch to install in left head on motor so you dont have to deal with toggle switches inside car. thats specially important when you let others drive the vehicle. i mean the 2 wire temp switch so it basically will be a stand alone system.

 

I have not seen 2 wire switches. The ones I referred to are single wire connections.