I get a lot of questions about doing the electric fan setups on TBI trucks. I have done a few now and have narrowed it down to just 2 routes that I recommend. I have tried too many of the aftermarket fans with either reliability issues or insufficient air flow issues so I dont recommend those although I will use a little 10″ HC7102 fan setup as a pusher on the front of my AC condensor in the grill hooked to my AC system to run when the AC is on with less amperage draw than running 1 of my big fans.
With all fan setups, I personally use a standard 4 pole relay which I get off the shelf at my local autoparts store for $5 a piece and I use 1 relay per fan with a inline fuse with 25 amp fuse per relay as well. I try to mount my relays next to the fuel pump relay under that plastic cover on the passenger firewall and use that main power block for my power for those relays but I have mounted those relays all over the engine compartment over the years.
On that ANY SWITCHED LEAD in the above picture, run a light gauge wire over to the PINK wire on your EGR solenoid which is a nice underhood 12v key on power source and since relays take nearly no power to engage that switch you can share that power with the EGR solenoid, I just jumper the power from one down to the next for that key on 12v. that wire I have marked ground on that relay picture, goes to the fan temp engagement switch. For 160 degree thermostat I use a hypertech 4026 and for 180 degree thermostat a 4028 or if you live up north where its COLD and want to use a 195 degree thermostat then you can use a stock fan switch for a 1988-1992 Camaro 305 TBI Vin E car. Placement of the switch, The Camaros with the factory switch locate it passenger side head over the number 8 spark plug much like your instrument cluster sensor is in the driverside head above cylinder 1. So I try to put it there but sometimes, I can’t get the plug out or the vehicle I am working on is just TOO hard to get to that area. I have mounted in the intake on vehicles that I am using a carbureted aftermarket intake that has a lot of holes to put things like that. I have also mounted it in the water pump as some pumps have a removable plug that you stuff a sensor in and finally, since these switches are just for fan engagement, I have drilled and tapped the thermostat housing and put it in between the hose and the thermostat since coolant will be flowing past thermostat before the fans need to come on. Just that aluminum is not REAL thick so when you tap it 3/8″ NPT and then screw the switch in. DONT get carried away. Never had a problem with that but I don’t regularly do that method. If your running 2 fans which is my preferred route, just like the 12v key on power you can run 2 relays off the same switch.
Now to the fan choices. You can go essentially 2 routes. First is easiest and my preference not just because its easy but 2 fans gives you redundancy that if one fails from either fuse or actual fan motor problem you do still have one to provide some cooling. I use Camaro LS1 fans. If they can keep those crazy modified LS motors cool they will keep your stuff cool. the picture in the truck is from my supercharged 6.0L project nitemare truck which has never had a engine coolant temp issue. Cost around $100 off ebay. Just search LS1 CAMARO FANS and you should find a set. Now when you get them they have a gap on each side for the Camaro radiator and I want my fans pulling air through the radiator so I don’t want any gaps. I use a sawzall with a long blade for more flex and I cut the ridge off the top and bottom and the flex is for cutting the piece out of the middle so the fans fit FLUSH to the radiator. you can see in those pictures on the one side of the fan (bottom on that top pic) 2 tabs. I had to do a wee bit of trimming on those but they will fit between the radiator and the lower radiator support. Then you just have to fasten the top, which I just use 3 good thick tie straps which are better invention than duct tape. My black supertruck radiator had a ridge on top that I drilled a small hole in and in my camaro fan shroud and strapped it to the radiator. The purple plum crazy truck didn’t have much ridge so I pushed my tie strap through the top row of fins and then over the top edge of radiator and pulled it snug. I tossed my original lower radiator fan shroud out and cut the top part back to where it just covered my radiator. As for wiring, Looking at that top picture the left terminal on those radiators is the 12v and right one is the ground. I just grounded the fans to the battery tray support.
Second fan option. which i haven’t completed yet but one of my customers did it on his tahoe and I liked how it looked on the vehicle and so I am testing it out on my 454 project truck. This option is using one LARGE fan. I sourced my from a Lincoln town car. Apparently Ford Windstar has a nice large strong fan too. Fan does pull a LOT of air. so I took both halves of the factory fan shroud and I used plastic epoxy from local auto parts store with 5 minute cure time and I epoxied both halve together. I used the original 4 bolts that holds the halves together to help make sure it stayed tight while epoxy cured and I have left them in for added support. This makes the shroud a little more rigid to support the big fan. I then bought me some 3/4″ by 1/8″ flat steel and welded me a little very basic frame for that fan to extend it out where I could bolt it to my factory shroud. Once mounted to my shroud, I filled the gap with foam insulation from lowes in a spray can. Note. I wasted about 1/2 can before realizing the foam wouldn’t setup fast enough to fill that large of a gap. You need to use duct tape on the bottom side to give it a form. so I didn’t get quite as much foam around my fan as I wanted but enough that I am not going to mess with it. I wanted excess so I could cut it more flat flush prior to applying some black paint. I let mine cure over night and the foam did swell and not look as bad as that picture which is fresh after spraying. The black paint also stuck well to the foam and with the shroud upright you can barely tell the electric fan is in the shroud. I haven’t installed in truck yet and will edit the page later but see no reason for there to be a problem but this route is more work but does give a somewhat OEM look.