Cooling Fan Power

[VixJeep]

Hi all. Todays project for me is to wire my aux fan up so that when the truck is running, the fan is running. When my engine was replaced, the fan was never put back in. I installed it, but can't find the original wires for it. The truck likes to heat up in traffic, so I feel better with it running all the time. It's an 88 Pioneer 4.0L

 

Is there a good source of power under the hood, or do I need to go under the dash with it? I'm alligator clipping it on to the battery now. 

 

Thanks in advance. Once I get this one done, I think I'm on to the hard projects. 

[GirsMJ86]

If you want constant power I think your best bet would be to wire it up with a relay by itself rather than tap into power some place else. If you wanted to you could also then stick it on a toggle switch on the dash then so you could turn it on after a few minutes or so for better warm-up speed during colder months and such. Don't forget there are empty batt/acc spots on the fuse block you could tap into rather than tapping into a preexisting accessory.

 

If it were me, I'd wire up a switch on the dash and a relay under the hood drawing power from the battery/solenoid so the fan was just controlled from the switch. This would also set things up for if you ever wanted to dual fan it or anything.

[relyt120]

If you want it always on with the truck I would wire it to a relay which gets power off the battery and switches from some accessory's power supply, such as the cigarette lighter. Relays draw very little power so it should not affect the lighter too much and you can always run an inline switch in the dash if you want to be able to control it for warming up like GirsMJ86 said. This way it would default to on when the truck is running and then you can turn it off by switching off the switch when needed.

[VixJeep]

I wasn't planning on putting a dash switch in, but then I hadn't thought about winter warm-up. The lighter might do the trick to pull power from. I also have a fused line from the battery to the stereo that would cover it. I'd just have to switch it on and off as I need it. 

 

I got in there looking around and found the stereo wire - and heard a vacuum leak. There's a dual plug going into the throttle body that was out. Plugged it in, and it killed the  engine. Looks like it goes to the MAP sensor (I think. In the middle top of the firewall), and the other side is plugged off. Looks like I have an additional "project of the day". It'll just barely idle when it is plugged in. I'll have to do a little research on this one.  

 

Thanks for the help on this one guys. 

[cruiser54]

A bad fan clutch could very well be your issue. Not the auziliary fan.

[VixJeep]

Thanks all. I have it going for now. Added a switch, so I can turn it off when it gets cold. 

 

By fan clutch, do you mean the A/C clutch that turns the aux fan on? Eventually, I'll figure out how it all goes and hook it up like it should be. For now, I just put the fan in and couldn't find any previous wiring, so I'm just getting it running so I can drive the truck while my Honda is in the shop. The A/C isn't running - got to put the new compressor in. It was overheating pretty quick. I found some vacuum issues and it's running a lot cooler now, just need to get it up over 12 mpg. I went from a Honda Fit at 34 mpg to the jeep at 12. I should be closer to 17, but I've got some work to do to get there. 

[cruiser54]

No. The aluminum dealie whopper that the metal fan bolts to.