Ok. I finally had time to install the electric fan timer. I used a wiring diagram from cherokee talk. I think it took 4 hours total, but I wasn't keeping track and I did it over 2 days.

http://www.cherokeetalk.com/forum/f6...fire-fix-9124/

the timer board cost $37. relay $6. 18 gauge wire $8. switch $3.19. instrument box $5. .fuse and fuse holder $5...I already had 12 gauge wire and all other terminal connectors and tools.

I used the 12 volt power supply (constant) at the dash for my switch and also for the power to the timer board. The 18 gauge wire was used for the timer board, as it hardly draws any current. The 12 gauge wire goes from the battery to the relay to power the fan, and then from the relay to the fan. I also used the 12 gauge wire to ground the relay.
I also used a nylon bolt to attach the box to the inside of the fender.

I adjusted the timer to run for 4 minutes. one push of the button and the fan comes on for the alloted time. I have not run the fan timer with the vehicle on. I have only used after I turn it off. I'm not sure if it will cause any check engine light errors, or other issues if the vehicle is on. I do not think it will, I just haven't tried it yet.

 

So what is this mod for? To cool the water in the radiator after you park? Why?

 

Why did you do this?

 

Help reduce heat soak maybe

 

Guys ive done the efan timer and vents in the hood and wraped my fuel line with header wrap all to reduce heat soak with little luck.next is precat replacement.GOOD LUCK !

 

I did this for the heat soak issue. I was getting it after a hot start in conjunction with hot outside temps. So now what I do is when I'm getting gas, or going to run into the store for a few minutes, I turn the Jeep off, and hit the timer button. The electric fan runs while I'm doing my business. I have the timer set for 4 minutes, but it is adjustable. I can also hit the timer button when i'm driving. So it's like the switch, but it's on a timer. I like the idea of running the e-fan after the vehicle is off.
I also want to put in hood vents, or a cowl. The fan is good for bringing in cooler air, but the heat really has no way to escape, except out the side of the hood where it meets the fender. Mine got so hot it looks like it melted the clear coat on the fender.
I also think the heat under the hood shortens the lifespan of other parts, as well as contributes to the weakening/cracking of the 0331 head. now I'm no engine expert, but the heat has to stress the head.

 

Ive got a timer on my efan set at 3 min .i think i will change it to 4 and see if it will help.i also have an exhaust leak after the precat flange.that probably adds more heat under there.

 

I wanted to put a thermometer under the hood to check temps with and without the fan. I actually bought one, but it doesn't work for air temps. The only thing I could find was an "i grill" thermometer, but it was more than I wanted to spend.

 

it seems to me that by running the e fan after the engine is off you are adding the heat that is in the radiator to the engine compartment...

 

no... eventually I will put a thermometer/temp sensor and prove that, but for now you just have to trust me

 

http://www.naxja.org/forum/showthread.php?t=1083426

here's a thread from NAXJA. I will PM marty and ask him where he got his temp sensors from.

 

Here is more info on Heat Soak. not sure how old this thread is, but if guys dont understand HEAT SOAK... read this thread

https://www.cherokeeforum.com/f2/02-...h-idle-180996/

 

Very interested in this mod for the E-Fan. How has it held up? Has it resulted in any CEL lights? Have you tried engaging the fan whith the ignition on?

Thanks,
J-

 

no check engine lights. the timer will engage the fan no matter what position the ignition is in. You can use the timer while driving, or when the Jeep is off. That's the beauty of it. When you turn the engine off, you can run the fan for a few minutes after to cool it down, or you can use it while driving if you notice the temp start to rise before the computer turns it on. I have my timer set for about 3 and a half minutes.

 

Excellent. I've been fighting the heat soak/hard start on occasion in ambient temps as low as 50*. I've been using my phone with a Kiwi wifi OBII and the Dash Command app to monitor the intake temps over the past week and the intake temp skyrockets upon shutdown.

At ~55* ambient after a :40 drive home from work I watched the intake temp at shutdown climb from 97* to 190* in ~12 minutes. Imagine what it climbs to in 90-100* weather.

I've already ordered the switch and will report back actual results on temp when complete.

Thanks again,
J-