What is the "easy way" to install a
manual fan switch - in terms of wiring?
Thanks!

 

its very simple, there is a single wire running to your fan switch on the passenger side of the block. splice into this wire with about an 20 gauge wire, and run that wire through a loom into to your passenger compartment to your switch. then just run a wire from the ground side of the switch to a good ground. i put my switch inside my ashtray, and grounded it to my seat post.

 

Is there a good reason I couldn't use a switch with a light on it?

 

Depends on the electrical characteristics of the bulb in the switch. You'd want a bulb with a relatively low resistance. You can just give it a shot & see. It's easy enough to temporarily wire it into the relay(s) at the firewall. The bulb shouldn't hurt anything -- it will either work or not. For anyone who'd like to see it, here's an edited schematic for the fan & HD fan relays:

 

I was thinking of using my defrost switch. I think I could hook it up that way, and use it's light.

 

I don't know how well that would work unless you started rewiring a few lines here & there because the integrated lamp in the switch is not wired in-line with the switch contacts -- it's controlled by an external timer. It cqan be done, but before you go cutting a lot of wires, I'd suggest putting a meter on the switch to make certain that it's not a momentary switch.

 

Better idea, just get a fog lamp switch and put it in the same place. It has a light on it. I'll go find the diagram for that. I have a manual somewhere.

 

How do you wire up a switch to turn the fan on if you have a stock single fan?

 

phlaxus...where are you getting these schematics...I think I could find them very useful.

 

jimp2001:
Just run a switch from terminal F on the relay to ground. When the switch is closed it will pull the relay in & power the fan. If you only have one fan, the wire should be a Dark Green/White Stripe and is typically on the firewall inside the engine compartment right next to the VIN. As it is a low-current line, you could use a T tap crimp connector, but since it's subject to water from being in the engine compartment, I'd suggest solder, tape and then place a zip tie around the tape to keep it from unraveling over time.

zrated383:
Those are from the Mitchell repair book. I only have the 91 Camaro with all engine choices, but most other third gens will track the 91 Camaro schematics pretty closely.

 

Thanks!

 

Don't suppose you have the pic for the fog lamp switch. I think I might try to temporarily (or permenantly) remove the switch for the rear defrost. since the connections are broken at the hatch end.

 

...

 

Any electrical gurus out there understand whether or not I can use that switch the way I intend. All I need to do is connect a ground to trip the fan relay. I dunno if there's enough current there to power the lamp. (using just the fog lamp switch)

 

OK...I posted the last schematic just as my girlfriend called last night so I didn't get a chance to say anything here. I typically try to edit these down to just the core elements, but since it sounds as though you'll be cutting & splicing a few lines then it's probably just prudent to post this much. The really bizarre thing is how interrelated the fog lamps are with the headlights. I fully understand not allowing the fogs on unless the marker lamps are lit, but this just looks strange. I would have just grounded terminal #2 (LIGHT GREEN wire) on the Fog Lamp Relay and called it done...

Now as for using the Fog Lamp Switch -- looks like a good choice. I don't have enough information to say whether the lamp in the switch will illuminate, but it does appear to be a good choice for a switch. EVen if the lamp doesn't light (or burns out), the switch will still turn the fan on. It's morning for me still & my caffeine hasn't kicked in yet, but I don't think there's a direct way to make the Fog Light Switch light come on with the fan. It would work with an external relay, though...but it's just not too direct.

 

Something like this should work...just make certain all your connections are good (including any pre-existing grounds you want to use). This circuit assumes that the resistance of the relay coil is somewhat close to the parallel resistance of the Fog Lamp Bulbs If not, the bulbs may be too bright/not bright enough and a resistor will need to be inserted into the circuit (on the yellow wire, most likely) to balance things out.

This circuit also has the neat side-effect of turning on the Fog Lamp bulbs whenever the thermal sensor and/or ECM decides to switch the fan on.

 

...

 

Well I went to my car bit supplier. They didn't have a fog light switch, but they are getting a car in next week that should have one. So it'll have to wait a bit. And my door wasn't ready.

 

Sorry to open up an old thread, but I'd just like to verify a thing or two. In the 1st diagram above, posted by Phlaxus, it shows the "coolant fan relay" on the left; I assume this is the one that comes on at a "normal" temperature, correct? I hooked up a switch to the wire at the temp sending unit on the pass side, and it turned on the fan on the right side, the "heavy duty fan relay" that comes on just before boil over (haha). Is this how it is supposed to work? I ask because 1) I still want one of the fans to come on at the prescribed temperature with no outside interferance (me) and 2) the blurb in the Tech Section said if I hooked the wire up BOTH fans would come on and they do not. Could somebody please weigh in on this and tell me if I've screwed something up or not?

Thanks....Eric

 

i just wired mine into the fan relay then a good ground right under the dash....mine is also a lighted switch and when i ran the wire to the fan relay i just ran it to the power on the switch not the acc. and its backwards like that though the light is on when the fan isnt on and off when the fan is on which dosent bother me to bad its kinda a reminder to watch the temp. it also maintains the other fan controls like engaging when air is on etc...

 

On the first schematic, if you place a switch on relay Terminal F going to ground, this will not interfere with normal operation of the fan. If the switch is on, the fan will stay on until it's turned off. If the switch is off, then the fan will come on with the factory triggers such as heat, A/C, etc...this is assuming that the factory setup is properly functioning, of course.

You can place the switch on just one relay, one on each relay, a DPST on both relays or even tie both terminals F together and run them through one switch. The last setup, though, will have both fans coming on together no matter what caused them to come on.

 

Thank You P, that answered my questions!