Just bought a 92 RS 305. The cooling fan stays on constantly. During the summer this would be fine, but now that it's cooling off I would like it to function normally.
They had tapped a wire into the harness by the ac drier and ran it to the fuse block and I took that out. Is there anything else that I need to be looking for ? There is a yellow wire above the fuse block (about 10ga) that was cut and spliced into a 10ga purple wire. Is this the culprit ? If not does anyone know what the yellow wire is ?
Waiting on my gm shop manual.
If any one has a cabin wire schematic they can email me while I wait for my book that would be great.
Any help is appreciated.

 

The only thing worse than tracing an electrical issue is trying to figure out someone's rigged up junk! Sorry you have to go through it.

Unless you are trying to make every little detail of this car perfectly 100% stock, I'd suggest wiring in an entirely new fan control unit. I put one in my 92 RS and it's been great (I did so because I could not get a fan switch to work, and was tired of replacing them).

The one I got is from Summit Controller and it's totally controllable, with the option of having extra switches in the cabin for fan always on and fan always off.

Then, after you get the fan working properly, you can go back one by one, remove the wire rigging that's in there, and determine if anything else is 'rigged' up as well. Good Luck!

 

Well I found the culprit today. The coolant switch wire has had all the plastic broken off it and the plug was resting on the frame. Now I need to know where the switch is or is supposed to be located on the right head, and if by chance you have or can get a picture that would be great. My other problem is that the parts listed at the store are not the correct style plug. Does anyone have any ideas about this or poss. a GM part number ?
Thanks
Brien

 

well id love to give you a picture but its a bi*** to get a pic without a lift, its gonna be in the head between the #6 and #8 spark plug just feel around on the side and if you can, use a mirror to look down there, it will just be a little connector with a single prong connection

there will also be the one ontop of the intake and that one runs to the ECM, beware of the gauge though, they can be off alot, i just wired my fans to the stock setup today and my gauge pegged at red which is like 260* but when i hooked up the tech II it only read at 218*.

Apparently the sensor for the gauge is between the #1&3 spark plugs but i havent really found the time to bother looking and i can tell you from experience on these boards youll get the run around on which one is which lol

You can get the pigtail for the fan switch from napa for like 6 bucks, just be sure to solder it and not crimp because its a grounding switch if i remember and if you crimp it and for whatever reason the insulation moves back and it grounds the fans will just kick on, hope this helped

 

I just ordered one for my 1989 305 TPI. Not sure it is the same but it should be.

Fan Switch GM PART# 10045782 $19

Also TPI parts should have a replacement connector for you wire. I think they are $12

 

??? you paid $19 for it? i paid $15 at my local napa for the switch and the pigtail

 

Yeah, got mine from GM.

 

eh its all the same in the end, a GM sensor works the same as a Checker sensor and it was cheaper lol

 

One more question on this issue. Where is the two wire coolant temp sensor supposed to be on the tbi engine ? I've located the two on the heads, but everything I read says there should be one in the front of the intake and I haven't found it yet.

 

the 2 wire sensor is the one communicating with your ECM and it belongs on the intake manifold by the Thermostat housing.

The single wire plug on the passenger side should have a slide on connector that you squeeze the sides hard to band into a circle and pop off, as for the other sensor i dont know much on that one, never messed with it

 

I know this is not the right spot for this question, but since I have good input so far.
Where is the stinking knock sensor?

 

i think its on the passenger side, alot of people mistake the fan switch for it and vise versa, the easiest way to tell is the knock sensor is in the block whereas the FS is in the head