I got a 1986 Iroc Z with computer controlled quad carb. I just recently got this car so I know very little yet about what may be hidden problems. When I got it someone had cut the wires going to the fan relay and twisted some of them together so the cooling fan would run (I didn't know that was why at the first) so I wanted to fix the wires the right way so I separated them. Then the fan wouldn't run period, I straight wired it (after replacing the motor thinking that was the problem) just to see if it was working. It was so I popped the relay apart and THERE WAS NOTHING INSIDE BUT AIR! Someone had removed all the guts from the relay. I took another relay and plugged it into the plug and the fan instantly came on BUT the key wasn't on and the car hadn't even been run. I noticed my plug going to the relay had only four wires (the fifth had like a plug off in it) but the harness had five wires and so did the replacement relay. I've looked at several relays at the junkyards and they all have five terminals on the relay and five wires at the plug. My question is Why does my plug have only four wires and five in the harness and how could I remedy this?

 

I'm really new to working on computer controlled cars and new to this board so any help would be appreciated. Anybody???

 

I believe all our cars' fan relays only have 4 wires. The relay and harness may be set up to accept 5 or more wires, but should only have 4 if you are actually looking at a fan relay.
Can you post a pic, so I can see? It sounds like you are going to have to do some wire tracing in order to solve this mystery...
Sounds like there is wiring crossed somewhere, or the replacement relay is fried internally (seen that before), making fan run while car is off.
btw, a new relay would cost you maybe $10 i believe, and take any guess work out of the equation...
Let me know how it is working out.

 

Without a doubt my plug only has four wires coming out of it BUT all of the other ones I've looked at have FIVE wires going through the plug. I know i'm dealing with the fan relay because I got the relay wired up temporarily to run when the switch is cut on and goes off when the key is off. I don't want to keep it this way It's just till figure the problem out. I am parting a 1986 TPI 305 auto Iroc that has five wires going to the relay plug and five terminals on the relay. but my 1986 305 computer controlled quad Iroc has only four wires in the plug BUT the wires coming out of the harness are five, (1)black with red tracer: to the fan, (2)redish orange with fusible link: to continuous power, (3) solid green: to ????, (4)green with white tracer: to ???? (5) another green with white tracer: to ????. The parts car has different colored wires going to the same fan relay. They are both 86's with 305's the parts car was 700r4 tranny and mine is 5 speed manual. That fact may have something to do with it.

 

I got a new relay and hooked it up but still wont kick the fan on and temp was on 220. Here's a picture of the wires. The two wires that are circled are both brownish with white tracer but the plug only has one brownish with white tracer coming out of it. These wires had been completely cut before I got the car so I don't know for sure how they hook up. the ones that are hooked up are self explanitory but the two circled ones are in question. The one brown/white wire I got connected has power with the key on the other wire has nothing and I don't know where it goes. If I could see a picture of someone's relay maybe I could figure it out but it would have to be from a non-fuel injected V8 car.

 

well I found my fan problem, I installed a new 4 terminal relay, I replaced the plug at the relay due to the terminals being corroded and burnt but the fan still didn't come on so I located the tem sensor and grounded the wire and the fan came on. So now I need to get a new sensor. Maybe that will cure it. Thanks to those who offered help to a newcomer. I also found the correct schematic for my carburated car on another post so I could check the wires. My repair manual didn't have the correct one.

 

i had the same problem with my 85 iroc.
what i did was buy a new adj fan relay hook up kit, and totally bypassed the sock temp controls. The kit was easy to install, and i even have a switch on my dash ,so i can turn on my fan manually!! Ill never have to worry about blowing all my coolant out at 230 degrees when the fan dosnt come on!!!!
so if you are still havin trouble buty on of these kits , there only like 30 bucks!!!

 

Glad you could make some progress with the relay deal. The relay you had looked like my fuel pump relay.
You can make a manual fan switch like I did, and/or you can also get a lower temp fan switch (that goes into the pass head)
fan switch options
There is also a stickie at the top of this forum called Willie's Total Fan Control. It explains in detail, how to make a manual fan switch. I was able to make one out of a fog light switch.

 

Well I got the new temp sensor and installed it. Cranked the engine and waited for the temp to rise. it got to 220 and still no fan, so I cut off the engine and turned the switch back on to trace the wires again. Then all of a sudden the fan kicks on! Hurray! I cranked the engine to see if it would cool it back down and it did so the fan kicks off. Temp got back to 220 and fan kicks on again. Problem solved. But what temp should the fan kick on? How could I tell if the gauge is accurate?

 

Hey, if you look at the url I listed in my last post, it tells what temp the switch should turn on at. Bear in mind, that the factory gauges in these cars are usually nowhere near accurate, but they are better than idiot lights ;-)

 

so 220 degrees is fine for it to get to before the fan coming on?

 

SuRe! If it gEtz uP To 260 And They Dont kIcK on TheN u haVe a ProbLem! 220 iS noRmaL!

 

220 degrees is still hot. think about!!! new cars run at about 160-180. Gm cranked up the temps of these cars to help with complete exhaust gas burning.
If i were you i would still get an aftermarket fan swtich and lower thermostat to get about 180-190.your engine will thank you for it!!!!!