how to hook up electric fan in my 84 to 87 swap

[tar baby]

so I swapped my 84 g.n over to a 87  intercooled setup . I have it running alright. I  am just wanting to hook up the electric fan I purchased so the relays work . as it stands there is no power to the stock plug on the 87 harness. because the 84 didn't have such luxury's   I was going to hook it up on a switch .. but I would like it to be idiot proof ... so if anyone has done this or has any info I would really appreciate some insight .

[TexasT]

Lets start off with the electric fan you purchased. Is it an 86-87 factory two speed with the resister and such? Is it one of the wrecking yard mopar units? Is it an aftermarket piece?

Electricity is like water, and the wire the electricity flows through is like a pipe. A relay is like a heavy duty switch that can be mounted near the equipment you want to power and switch on and off. This allows one to only have to run the heavy wire from the power source to the equipment and to ground. Then lighter less expensive easier to work with smaller wire can be run to the switch at a remote location such as in the cockpit to a lighter duty switch since it doesn't take aa much power(water, electric) to trigger the relay as it does to power the equipment(like the fan or lights or fuel pump).

The fan relay for the 86-87 is on the pass fender next to the fuel pump relay. I'm not sure on the 84-85 what the relay setup is like or if there even are any on the fender. You will have to check that out. Might like to add what the later cars have or go full custom. I would carry a spare relay with as some can be hard to get or at least take time when you need it "now".

I would take my power right from the back of the alternator or + battery terminal depending on where the input I on your fan setup. Did this setup come with any instructions?
A good ground is essential in any electrical activity. This might be run to the fender to the ground bundle already there. Again in not sure on the early cars but I know on my 87 they're run to then fender. You will have to look at your situation.

As far as making it turn on and off I would want it to do it automatically. At least one mode I would want to come on so it didn't over heat if someone else was driving it. Then you can run the other mode off a switch. I looked at a set up with a thermostat that would turn it on and off for my daughters car. It quit coming on and was over heating. Found it on amazon. I'll look for a link.

[daveismissing]

Find out how your 87 chip is programmed to switch the fan on.If you got an 87 harness it should all be there?

[tar baby]

The fan is a aftermarket  derale unit  . under the hood its all 87
..   I was just curious about powering the original fan  wiring  . but ill just tuck it aside.  and run wire to the switch .

[Steve Wood]

Pretty simple wiring

http://www.vortexbuicks-etc.com/fan.htm

Sent from my LG-H810 using Tapatalk

[tar baby]

thanks Steve

[Steve Wood]

As you have a single speed fan, it's easy.  Just take the low speed relay that is triggered by the ecm and take the output from the relay and connect it to the fan.  When the temp that is programmed into the chip is reached, the ecm will trigger the relay and turn the fan on.

Ignore the delay relay and the high speed relay if you are running a single fan.

If you have the factory wiring, power to the relay will be thru a fusible link.  If you don't have the factory fan wiring, then a feed off the battery thru a 50 amp maxi fuse will suffice.

[tar baby]

thanks again.. this clears it up for me .