Custom headlight/fan relay harness build

I thought I'd share the addition to my pickup that I finally got around to building. I've noticed that both my 87' ram 50 and 88' mighty max have wiring under the dash that gets very hot when using the headlights, especially the high beams. I've cleaned the connections between the switch and body harness, but the problem persists. I decided to add some relays to reduce the current flowing through the factory wiring to help with this and to give the best light output possible through the upgraded Philips crystal vision halogens I have installed. I know that there are LED retrofits and other alternatives, but I really like having either sealed beams or the glass lens ones with an H4 bulb like the ones from Cibie or Hella, and I know Koito has a nice set available now too.

Also I recently went on a search to find a good fan to help the AC condenser at idle and low speed. I wanted a fan that was not aftermarket so if I needed to replace the motor or something, I would be able to easily find a replacement. after roaming around the junkyard, I found a 93' Toyota with a condenser fan that looked like it would fit the bill perfectly! It appears to be used in pickups and 4runners from the mid to late 80s through to the mid 90s and is readily available still as an assembly or even just the motor itself for around $40. I also like that it uses a round shroud to minimize the amount of surface area blocked when the fan is off. the shroud is also made out of metal, perfect for cutting and welding to for mounting!

For the relay box and fuse holder I wanted to also avoid using aftermarket stuff. I wanted something that would hold up to being in an engine bay and not look tacky or fall apart after a few months or years. I didn't find a fuse holder that was factory equipment in a car that would do what I wanted so I did go aftermarket there. I ended up going with some MIDI fuse holders that snap together although I probably would go with a blue sea systems 3 fuse holder that I found later, It used the same fuses that are used everywhere else in our trucks, ATC I think they are called? The relay holder came from ebay out of a mitsubishi lancer hatchback from 08' to 17' although I think it was used in others like the Outlander etc. there are versions too that have just 2 relays and a large fuse that would be perfect for use as just a headlight relay. The one I got has 3 relays, 2 big ones and a standard Bosch style "cube" relay.

I hate doing mods that alter the body permanently on my vehicles, so I like to make brackets that utilize existing mounting points instead, plus it gave me an excuse to use my new welder I got that's just been sitting! So I made this bracket! http://www.mightyram50.net/vbulletin...id=28427&stc=1
Note the mounting tab for the relay box, my relay box came with the mounting bracket from the car it came from so just drilled out the spot welds and saved it for my trucks bracket. I'm sure one could be made using a piece of strap steel the right with and thickness and drilling a hole in the right spot and filing it into a "D" shape so the plastic locking tab will lock it into place

I made the bracket angled to keep the power feed for the fuse holder out and away from anything that could chafe the wires before they could reach the fuses! Here's what it looks like with the parts installed:
http://www.mightyram50.net/vbulletin...id=28428&stc=1
I also used new ceramic connectors for the headlights and a reverse H4 connector to plug into the factory harness to control the relays in the box for the relay harness.

Next post ill show how I mounted the fan and How I control it!

So for the fan mounting, I did have to modify the support bracket that goes right behind the grill. It is easy to replace, since it is held on by just 3 bolts, so its not an issue for me if I decide to do something different in the future. here's how I did it.
http://www.mightyram50.net/vbulletin...id=28429&stc=1http://www.mightyram50.net/vbulletin...id=28430&stc=1
You can see where I cut the bracket. I forgot to get a picture of the finished part, but I just bent in the 2 sections and welded them up and filled in the resulting gap with a piece of sheet metal cut from the piece I cut out from the bracket.

Here is the fan. I removed almost all the mounting points except for the one that the fan motor connector clips to, it actually got used as a mounting point later on by installing a rivnut in the hole on it that sits at an angle. I utilized the rubber mounts that came with the fan by cutting and welding them to different spots as seen in the following pictures. also note the bracket that attaches to the condenser. This uses the existing screw holes in it but with slightly longer screws to reach the threads in the rear of the condenser.
http://www.mightyram50.net/vbulletin...id=28433&stc=1http://www.mightyram50.net/vbulletin...id=28435&stc=1
The fan relay I decided to control with the Idle up solenoid. It gets its power from the same circuit as the compressor clutch, but on the 87-89 pickups, its ground is controlled by the ECM. this means that once the engine is above a certain RPM or throttle position (I'm not exactly sure which), both the idle up solenoid and condenser fan turn off. This is good for fan wear, relay wear, fuel economy, etc. I had asked about different options in a different thread but decided to go with this option for now at least. It does seem to work good so far. I simply made a "T" harness that puts the fan relay coil in parallel with the idle up. Speaking of relay wiring, I decided to use one of the big relays for the fan and the other big one for the high beams, this leaves the smaller relay on the low beams. The smaller relay has plenty of current capacity for the low beams and the fan, I'm sure, has a pretty large current draw on startup. This should prevent any of the relays from failing too soon.