Which wire signals the fan relay to turn on?

[daytonaturbo87]

I'm in the middle of chopping two engine wiring harnesses together. It's going well for the most part, the harness is going into a rampage. I've gutted what I needed to out of the rampage's wiring harness, so all that's left is the lighting and starter circuits, and I'm adding in the engine control section of a harness from a 87 lebaron 2.2 T1. It looks like the lebaron I pulled the harness from either had an overheating problem or the rad fan relay was dead, cause they had rewired the rad fan to run constantly. I don't want that for the rampage, I want the computer controlled rad fan scheduling, so my plan was to just find the wire that sends the signal to the fan relay to turn on. I want to buy a relay at the local parts store, and have it turned on by the signal wire that went to the stock fan relay, then add in the constant ign run power and ground wires to the relay myself. I've looked in my wiring diagram, but for some reason it doens't show the fan relay circuit. Which color wire is the signal wire and where does it come from?(logic module? power module?)

Thanks.

[MiniMopar]

I believe it is dark blue with a pink stripe. It goes to the LM.

[JDAWG]

that is correct, the relay is grounded to turn the fan on, may want to splice in a switch to manually turn it on also, but still have computer control, look at this written by saxhouse http://www.sv-td.com/members/images/.../fanswitch.htm

[daytonaturbo87]

that is correct, the relay is grounded to turn the fan on, may want to splice in a switch to manually turn it on also, but still have computer control, look at this written by saxhouse http://www.sv-td.com/members/images/.../fanswitch.htm

yep, that was the plan already, can never hurt to have a back up manual control.

[Whorse]

Just did this in my 85 GLH and testing it to ground does in fact work. Nice thing is it won't work with the ignition off, so no risk of draining the battery. The hardest part will be running it through the firewall. I might try and use an empty spot on the bulkhead connector. Has anyone tried this?