I bought a set of electric radiator fans at pull-a-part, I got them off of a 2004 Cadillac DTS. They were about $30 with tax. I messed up, and also got a relay block with only 4 relays, it was $25 as they charged me for a fuse block with relays. I thought this was high,but had I bought 4 separate relays with the connectors, it would have been about the same price, so oh well. I started digging though my junk boxes in my shed, and found plenty of wire to connect everything. I wired 2 of the relays ( one for each fan) and I activate these relays with a toggle switch on the dash. This is wired on an ignition switched wire, so that the fans go off when the key is turned off. I have a thermo switch on order, and when it comes in, (next week I hope) I will install it in the thermostat housing. I bought an extra housing to do this with. I will weld a collar to fit the threads of the thermo switch when it comes in, and have this trip the relays so the fan comes on at 185 F, and off at 175F. I have a 170 degree thermostat in my truck. I taped into the AC compressor positive wire, and tied this into a 3ed relay. I tied this relay into the trip wire for the other 2 realys so that when the AC compressor kicks on , the fans will turn on also, but will not back feed the AC compressor so that the compressor would not come on when the fans come on from another source. I ran 8 gauge wire to power the fans, and some small wire to trip the relays, about 14 gauge. I went to a local automotive audio shop and bought 2 large blade fuse holders for my positive supply wires. They were $10, All of the relay switch wires are fused, from the source where I tided them in. I took the set up to work today, and built some custom stainless steel brackets to hold everything in place. I used the OE bolt holes that held the old fan shroud for the new stainless brackets that I fabbed up. I also had to do a little trimming on the DTS fan shroud to make the SST brackets fit them securely. Although the DTS shroud is about 4 inches shorter then the OE truck shroud, I just added a small piece of foam insulation to hold the DTS fan shroud off of the radiator a bout 1 1/2 inch so that air from the bottom 4 inchs of the truck radiator, had a way to flow. It seams to all work well so far. So all of this cost me about $65. Keep in mind I had all of the wire laying around, and I am a certified welder. We do a lot of stainless steel work at the shop where I work. I have access to all of the equipment need to pull off a job like this. I used scrap stainless steel we had in the scrap bin. I also soldered and used heat shrink on all of the connections, except for the wire lugs I need to make the connections for power supply, or grounds, and I used some old copper line I had laying around to make the big lugs by flattening one end, and drilling a hole on that side. I also zip tied and used silicone to mount the relays in place. Here are the pics.
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