lt1 fan toggle switch wiring

**93TransAm** · 12-27-2011, 06:34 AM

I was curious as to what you guys think the best way to wire a toggle switch for the coolant fans is on a 93 lt1 only high and off settings. More specifically I want to make sure Im going to splice the correct wire. Im assuming the yellow wire off the temperature sensor on the water pump. Im all set and ready to go with the harnesses unhooked off of all the nearby electrical units and unsleeved. I have my wire cutters, heat shrink tubes and electrical tape and just want to make sure before i cut into anything. Thanks again guys

**93TransAm** · 12-27-2011, 07:08 AM

or would going off of the fuse box be better. I know this has been answered before but I'm having a hard time finding the info. And i don't really feel like spending $70 on the SLP wiring harness especially being my fans only have two factory settings.

**Knight** · 12-27-2011, 08:13 AM

I'm not sure of the wiring on the LTx motors, but if it were me, I'd find the power wire going to the temp. sensor and splice into that to the switch, then out of the switch splice into the wire going out of the sensor to the fans. All you'd be doing is bypassing the temp. sensor when you use the switch. And you'll retain the use of the temp. sensor when you aren't using the switch.

**93TransAm** · 12-28-2011, 05:07 AM

that's what i was thinking too, but the yellow wire I assume is the signal to the PCM and the black is the ground. so should the yellow just be treated as the power? Or would it be more feesable to splice into the ground wire and run that to the switch and run its own power off of the battery? And if so would it matter which way it went on the switch being theres no designated on or off position on the switch? Just switch it if it doesn't flip on the direction i wanted? also should i be safe and run an in-line fuse on the power end to be safe? I do motor builds and their operations fine but when it comes to playing with wires it always freaks me out. I know theres guys out there that have done this before, the problem is getting them to read this thread. :P

**Knight** · 12-28-2011, 05:10 AM

I would wire in an in-line fuse. If you have axcess to a multimeter, you can check to see which wire is the power wire.

**93TransAm** · 12-28-2011, 05:24 AM

hadn't thought about using the multimeter to check that. Also I was going to use automotive 10 gauge wire. Think its enough or too much? And to fill you in on why I'm doing this I had a custom tune for 180 on 160 off but i had a spark plug wire arch out and fried my pcm chip so im back to stock chip with temperature settings that are way too hot for what I'm accustomed to.

**Knight** · 12-28-2011, 06:18 AM

I don't know what the amp draw is for the fans, but I can't imagine it being too high. 10 should be fine.

**93TransAm** · 12-29-2011, 07:52 AM

Yea I checked the fuse box on my way out and it had a 10amp fuse for the fans. So i just bought the fuse holder and a pack of 10amp fuses, $5 all together. Thanks for the help Knight.

**Knight** · 12-29-2011, 10:30 AM

No problem.

**93TransAm** · 01-01-2012, 11:21 AM

Just to update: (battery unhooked) I started by tapping a hole in the firewall right behind the brake booster. I had to remove the two panels under the dash on the drivers side. Using a metal cloths hanger straightened with a slight curve on the end, I attached the 2 wires and the heat protective sleeve with tape and pushed it through. I ran that across the motor to the positive accessory terminal right above the battery using an inline 10amp fuse right before the terminal. running the 2nd wire towards the fuse box with another sleeve attached behind the brake booster. ziptied the one to the harness across the motor to keep it clean. then attaching the other one to the headlight wiring to keep that clean. lifted the fuse box on the drivers side under the hood and found the two power wires to the relays for the 2 fans. spliced those to the 2nd wire previously mentioned. then spliced the black wire for each to a wire i ran behind the headlight to the ground that is right next to it. then went back into the car and attached one positive to each side of the toggle switch. Now when i flip the switch i can turn on both fans whether or not the car is running. the best part is the computer can still do its thing and i have control whenever i want. If anyone else does this just be sure to shut them off when you leave the car. Put the switch where ever you want. took about 3 hours with figuring it all out and install and cost about $20. Its totally professional looking, still uses the relays and has the in-line fuse for protection.

**5.0THIS** · 01-01-2012, 03:17 PM

After reading that, I know even more why I went with the SLP switch. Took me maybe 15-20 minutes to install (time is money), no hacked up wiring harness, dont have to remember to turn them off, no additional holes in the firewall, high and low fan control, and abiity to return to stock in minutes.