Jeep Electric Fan mod

[Sodell]

Has any one done on of these fan mods on a 73-87? Jeep 4.0 electric fan..http://67-72chevytrucks.com/vboard/s...=254617&page=5

[1970pelle]

I use the 2000-02 Jeep WJ (Grand Cherokee) cooling fan. Its larger in size and puts out 3500 cfm. There not that expensive, if you get the recall version.
The recall # F25 and the fan part # CBG4F250.

I went to the local pick a part and found the wiring harness and plug for the fan motor. They used that fan back to 1999 on ZJ with heavy towing package.
I'm also using the Volvo 2 speed fan motor relays. Also pick up at the pull you own parts place. I found the CKT diagrams here, by doing a search on electric fan wiring.

I hope this helps. Ken

[72blazerblue]

Originally Posted by 1970pelle

I use the 2000-02 Jeep WJ (Grand Cherokee) cooling fan. Its larger in size and puts out 3500 cfm. There not that expensive, if you get the recall version.
The recall # F25 and the fan part # CBG4F250.

I went to the local pick a part and found the wiring harness and plug for the fan motor. They used that fan back to 1999 on ZJ with heavy towing package.
I'm also using the Volvo 2 speed fan motor relays. Also pick up at the pull you own parts place. I found the CKT diagrams here, by doing a search on electric fan wiring.

I hope this helps. Ken

I am wanting to install the 2 speed Jeep Grand Cherokee fan in my 1967 C-10. Mainly because it fits perfectly in the shroud.

I was also planning to use the volvo relay with the dual speed BMW switch.

Does the BMW switch work with the Jeep fan??

[bnoon]

I used a dual fan unit from a 90's Ford Aerostar minivan. Cost was only $24.99 and mated up really easy to my factory radiator. I used a piece of angle aluminum for the top, drilled a few holes and mounted it to the factory shroud mounting holes. For the bottom, two pieces of 2" wide aluminum flat stock bent to 90 degrees and about 5" long sllipped into the stock bottom mounts.

I use my 5.3 PCM for controlling it, but I have used a dual fan controller from Advance in my prior BMW M3 and it was only $35.

[gmachinz]

A much better fan is the 2-speed Crown Vic fans. Ive used them on these 73-87 trucks with no issues. I'm currently outfitting my 86 K10;with a diesel radiator and a massive 6000 CFM dual 14" F150 fan assembly just to do it. I want to use the biggest freaking fan assembly at my disposal to see how well my 3-speed fan harness handles it. I'll post pics soon of the mockup!

[bnoon]

Originally Posted by gmachinz

A much better fan is the 2-speed Crown Vic fans. Ive used them on these 73-87 trucks with no issues. I'm currently outfitting my 86 K10;with a diesel radiator and a massive 6000 CFM dual 14" F150 fan assembly just to do it. I want to use the biggest freaking fan assembly at my disposal to see how well my 3-speed fan harness handles it. I'll post pics soon of the mockup!

What are they rated at for CFM/amps on the Crown Vic fans? I know the dual Aerostar ones move some serious air! I set mine at 195 and I've only ever seen one degree over.

[gmachinz]

The CV's are rated the same as the T-Birds.....4200-4400 CFM. They have an S-curve design and a really deep shroud for an electric fan too! They fit on a stock 73-87 truck 3 or 4 core just fine covering about 80% of the fin area. They were designed by Siemens for severe police duty so they are among the best fans you can find along with the aforementioned T-Bird and of course the Lincoln Mark VIII.

My low temp was set to turn low speed on @ 200 on my gauge and when it kicks on, I counted to 8 seconds and watched that needle go down steadily and the fan shut off at about 185. After the initial on/off, the truck never got over 195 and never needed high speed unless I turned by AC on. Even then, I've wired my system through a trinary switch for high side line pressure in parallel with the high temp trigger and low fan speed was still enough to maintain a low enough head pressure (175 psi was the trigger) that high fan speed was rarely ever engaged-that was last summer.
So now, just to see it done, I'm running a mammoth radiator/fan combo....oh yeah. Frosty AC no matter the humidity!!!

[bnoon]

I think I'm going to rewire my dual fans into a "both on low, both on high" instead of the current "One fan on high, both fans on high" setup. What sort of resistor/volt drop/amp draw would you suggest I be looking for on the low side for a dual speed setup?

The dual Aerostar fans move enough air that it forced me to better seal off the holes in the firewall after my 5.3 conversion. The thing was like a heater kicking on forcing hot air into the cabin! LOL!

[gmachinz]

As youre aware the amount of amperage draw depends on a combination of a few things-most importantly is wire size and amount of brush wear in the motors themselves. However, assuming a healthy dual fan setup, I'd say you can expect about a 15-18A on low and 24-26A on high speed. Having both fan on at all times increases the surface area of the entire radiator from which to pull heat through. I "get into debates" all the time on other boards about "that's how GM used to wire fans one on, then the other." so I respond with "....yeah....USED TO!" lol.....from a standpoint of thermal dynamics, a single large fan will ways have the ability to outperform even dual fans all else being equal but, room is always a concern. Luckily for us, these trucks (73-87) have plenty. A large dual fan assembly just plain fits better and with that I ways suggest wiring in series for dual speeds.