Oil Cooler Fan Wiring Question

CrossT · 08-24-2003, 08:36 PM

I have, for the most part, installed an aftermarket fan in front of my 86 fender mounted oil cooler. The install was not that hard, but took a bit of time. I used a Perma-Cool 8" fan and drilled three holes in the cooler bracket to mount the fan. I had to extend the mounts for the horns by about one inch to allow them to clear the fan. I have opted for a manual toggle switch on the dash as opposed to a thermo-activated device.

Install Picts:

I have not finished as I am having trouble with the wiring of the relay and switch. Any help in where to attach the wiring to the relay terminals would be appreciated. Unfortunately, the instructions that came with the relay don't exactly match the relay -- and they seem to contradict the instructions in the tech article on this site. I hooked it up per the relay pkg instructions as well as I can determine. No dice. I hooked the fan directly to the battery and Gnd -- works great. Unfortunately, the relay's instructions don't refer to the terminals' numbers, so, not too useful.

There are five terminals on the relay and three on the switch. Direct help in terms of what to hook to what would be great. :]

Relay
30
85
86
87
87a

Switch
12v
Acc
Grnd

thanks,

todd
========
86 cpe

cowtown · 08-24-2003, 09:12 PM

85 and 86 are relay's control coil terminals...wire your switch up to them with a 12V power source.

30 and 87 are the relay's high-current teminals...wire your fan to these terminals. 87a is a terminal that is closed when the coil is open and vice versa. In other words, if you hooked up your fan to 87a it would run when the switch controlling the coil (85 and 86) was OFF. You won't use 87a in this application.

Early_S_Man · 08-24-2003, 10:32 PM

Todd,

By DIN convention, terminal #85 of the relay is ALWAYS GROUND! It won't make any difference, unless your relay happens to have a built-in suppresion diode -- like the red fuel pump relay! Many aftermarket relays from Hella, Bosch, Aromat, and Potter & Brumfield have the built-in diodes and must be wired as per the convention ... or you risk blowing fuses or a fire hazard when the diode is forward-biased by having terminal #85 connected to +12 Volts!