Hey all,
I'm a new member here, so I'll give some background. Last year with the help of some very good friends, I swapped a warmed-over '87 LB9 TPI motor into my '85 Monte SS. We used the stock F-body wiring harness, and everything is hooked up to be emissions-legal (AIR pump, cat, etc.). I'm running a RobertShaw hi-flow 180* thermostat, and she's cool on the road, but like most of you, she get's hot sitting in traffic.
Can I run a jumper wire from the ground wire on the Primary Fan relay to the ground on the Secondary Ran relay to activate both fans? Is it really that easy?

Thanks in advance,
Steve Ragusa
'85 TPI Monte SS
www.bowtiepower.com

 

It really is that easy. If you have a stock PROM in the computer, your primary fan won't come on until 223 or so anyway. If you jumper the grounds on the relays, and add a low temp fan switch (GN's for example have a 208* fan switch that installs quite nicely in the passenger side head, which is what I'm using), both fans will come on at the 208* turn on temp.

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-Jason M. 1991 Camaro Z28

 

Yea, that's all there is to it.

If you want to get a little fancer, you could add a little more control to this fan.

With an on-off-on "center off" toggle switch (SPDT), wire the center or "common" contact to the second fan relay coil ground (the positive side I presume will be +12 ignition). This will be switched ground to turn it on.

Now, use one of the other contacts and connect it to ground.

Use the other contact and connect it to the first fan relay coil ground that is switched to turn it on.

This will allow you one of three possibilities.

1. Fan is off when the switch is off (center position).

2. Fan is manually on in one position.

3. Fan is automatically on in the other position.

This way you can keep it off until you need it (less strain on the electrical system and fan motor) and it'll give you something to do while sitting in traffic...

The way I have my two fans set up are:

FAN #1: Controlled by a 200° on 185° off coolant fan switch (from Sumitt - JET -60600).

FAN #2: Controlled by the ECM with stock settings.

I also have two toggle switches so I can turn either on manually.

This way, the passenger side always comes on first (lower turn-on temperature). But I can always turn on the drivers side (this won't come on until ~220°F) if I'm stuck in traffic and I see that one fan is not keeping it cool enough).

Or I can manually turn either fan on whenever. The only thing I can't do is turn the fans off. That would have required running another wire per fan relay to the switch as well as changing from an on-on (on-off) to an on-off-on action toggle switch. I can't think of any situation where I'd want to manually switch the fans off, so I didn't.

I mounted two minature toggle switches where the fog light switch was using a piece of 1/8" plastic fabricated to fit in the opening and painted flat black. (I never used the fog lights so I removed this switch.)

Just a little "food for thought".

[This message has been edited by Stuart Moss (edited June 17, 2001).]

 

Hey Jason,
Thanks for the info! I'll try it as soon as it stops raining up here. Will post back tomorrow with the results.

SSeeya!

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Steve Ragusa - '85 TPI Monte SS
Way too many mods to list...check out www.bowtiepower.com for all the info!

 

Well guys,
Thanks for the info! I ran a 10ga. jumper wire between the two grounds, and used the splice terminals to go between them. Works great, and I can actually see the temp going down now.

SSeeya!

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Steve Ragusa - '85 TPI Monte SS
Way too many mods to list...check out www.bowtiepower.com for all the info!