I for the most part have successfully swaped wiring harnesses from an 88 iroc to a 85 Z28. I need to know if the cooling fans require a temp switch, or if the computer controls that function. If there is a switch then there is one wire that I think it could be the one for the switch, being that I didn't know what it was hooked up to I didn't label it like everything else. I believe it is a brown wire, and where would the switch go if it is needed?Could anyone help me out on this one?

 

Does that brown wire have a round connector on it? It may be the timing bypass wire

The 88 harness may have a dark green wire coming off the relay to a fan temp switch

 

well when I removed this wiring harness from the wrecked hulk it was in, the wire had no connector on it. The wire looked like it was cut, I am not sure if the wire is brown, or if it is red and has just faded. I went to the local chevy dealership but the could only bring up the ecm diagram on their computer. The chiltons repair manual does not show me what this wire is, but I used it to repair the rest of the harness. I asked the representative I was talking with at the dealership if the computer turned on the fans, or if the switch controlled that function. I was told that the computer did, but I am still not sure, Autozone carries a cooling fan switch and they told me it was factory. Well if I had the right wiring diagram I could probably figure it out, but I don't so I am asking everybody who would possibly know what I am talking about. I have had more help from this forum than any of thepeople that should know what I am talking about in this town.

 

Where is the wire at? Left side front by the heater box? front of motor??
Do you have a newer chiltons with the "typical wiring" diagrams? Look in the front cover and see if its published by haynes. Haynes just totaly ruined a good manual. I can scan and e-mail a diagram from my older chiltons if needed. I looked and it shows a switch for the coolant fan.

 

ok, the mystery wire is right next to the knock sensor, it is in the same batch of wires. right in front of the starter. Oh and my chiltons is published by W.G. Nichols, Inc. If you have a different set of diagrams I might be able to figure this thing out. If you want to send them my E-mail is jedigreyrobes@yahoo.com. Yea, I have been getting conflcting results from certain repair manuals, sometimes I have to go to the chevy house and annoy them, but they don't always know what I am talking about, being that my vehicle is not what they are used to working on.

 

if its brown, it might be the oil pressure sending unit wire? im not sure, but its not the fan switch. if in doubt of the fan, just run it on your own switch (great for when you turn your car off and need to cool the water in the rad).

 

Is it about a 10 gauge size? It may have been a fusable link that broke or was burned

 

The guy who hadmy car before me installed a manual switch for the fan. He put it to theleft of the steering wheel right under the headlight ****.

 

yea it is a pretty small wire, everything works except for the fans, the motors are good on them because I checked them with a jumper wire. If the 88 5.7 liter iroc engine has a temp switch then that is the only wire it could be, I have no problems with my instrument cluster or any trouble codes.

 

I think the electric fan may have a fusable link. Did you check them?