I have been reading online now for about 25+ hours on the ups and downs of installing this fan and I have finally found what I think is the best write-up...granted it is on a YJ but it is very comprehensive.

http://www.jeepforum.com/forum/f12/v...-swap-1373350/

My question relates to the wiring diagram he created...am I supposed to have one 87/87A relay or two? One for both hi/low speed kind of thing? Or do I need two; one for each speed?

Is swapping in a 136 Amp ZJ Alternator necessary for this setup?

Anyone who has done this feel free to chime in on what you did.

 

Day bump

 

So the answer to your question is that the person who wrote up that guide used two relays, but neither of them are necessary unless you want the fan to a)only be used when the ignition is switched on, and b)have an "off" switch for your fan.

The switch is completely unnecessary in my opinion, as you'll need to fuse the power supply wire anyway, and should you need to turn the fan off you can simply pull the fuse. How often are you really going to want to switch off the fan? If you cross a boatload of water, or you just want a shiny switch on your dash, go for it.

So that volvo fan relay is basically two regular relays. It just has two separate trigger wires, one per fan speed. It can only be used for a ground switch setup, so you cant feed 12v+ to trigger the fan. That relay has three input wires and two outputs. The large red input wire is the power feed. That writeup wired it to a relay which was powered by ignition power instead of straight battery power. That's what made the fan only run with the key on. If you were to put that power supply wire to straight battery power (through a fuse of course,) the fan would come on whenever the temp sensor was above its set temperature. Depending on the temp of the sensor, the fan will turn on and off a few times after shutdown, which is beneficial in that it fights heatsoak, but adds wear to your battery (worth the tradeoff in my opinion.) The other two input wires go to the temp sensor, one triggers low speed, the other high. The two output wires go straight to the fan, one for low, the other high. The coolant temp sensor used will need to be a two stage (three wire is best, as two wire will require the ground to take place through the threads. So if a hose splice is used, you'll need to run a ground wire to it, and because it's grounded via threads, the use of silicone/sealant can prevent conductivity of your switch.) One wire will be a ground wire, the other two to trigger high and low speed.

Long story short, you can wire it without the extra relays easily as long as your charging system is up to snuff and can take running the fan a few times for about 30 seconds each after shutdown.

 

Only one relay. The switch is to turn the fans off for water crossings. The fans will not run after the key is turned off. I have the same setup wired just like that but im using a vovlo fan.

 

Thank you for the thread & response Brokenrex. I've been contemplating this for a while but never have since I am stupid when it comes to anything electrical.
You have saved me (& I'm sure many others) a lot of reading & headaches.

 

In the writeup, the guy says clearly he used two relays, one with ignition power on the positive trigger side and a switch on the ground trigger side. Power runs through that relays feed (pin 30) and out its output (pin 87) to the positive trigger of a second, higher amp relay that actually feeds the Volvo relay power.

Again, his setup unnecessary in my opinion.

 

Check out Martinbuilt on YouTube. I believe he will answer all your questions.

 

Yeah checked out Martinbuilt on youtube but like the posted setup more. Plus I found one of the '"original" write-ups on a rx7 forum.

I have found a ton of great information today though on perhaps the toughest part to source, the upper radiator hose inline fan switch housing that is found in a saab 900 85-94 model years. It isn't made anymore unfortunately and that poses a huge issue for anyone who cannot find this car in the JY. This part is needed for the 3-terminal fan switch with part number 201-1266 because the switch is big... M22x1.5 big.

I am headed to the JY tomorrow to find as much parts as possible and will get back to everyone. I may do a write-up on this with either the taurus 3.8 or volvo fan, whichever I find. That way it would include every part number and website link for as much as we could want...or maybe I am just over analytical...

Brokenrex thanks for the info, I guess I wasn't including (in my head) the volvo controller as a relay. I will do that complicated setup though because I do want the temperature controlled option as well as the in-cab hat switch option.

 

I feel like a damn pirate today. I hit the JY and just scooped up the fan and shroud with the fan controller out of a 97 Volvo 850, the inline housing out of the 89 Saab 900S, and the fan switch pigtail out of a 02 Audi A6 quattro for a whopping total of $27.74.

Not to mention another Volvo fan controller and some relays and crap too.

Goodness I love JY's.

I have determined that I will indeed do a super extensive write-up that will include part numbers, vehicle models, and alternate parts found online with url links. and pics of course.

 

Looking forward to it

 

Looking forward to it

 

Looking to do the Volvo fan swap and had a couple questions. I don't want to cut off the mechanical fan pulley (don't like the belt re-route concerned about the serpentine belt in-print on the pulley). Has anyone done the conversion without cutting the the fan studs?

Also, what are there options for using the stock water neck housing to control both the low and high speed fan controls. I know I can used either a VW or SAAB water housing put in-line to the top radiator hose.

 

Here is what I did on mine. https://www.cherokeeforum.com/f5/fin...nstall-195441/





Max

 

Hmm I didn't even think about this. My father and I had a Fox Body Mustang we just sold to buy a Cherokee and I have a Taurus fan and Volvo controller I bought to install but we never got around to it.

So can we safely run this combo on the XJ?

 

yup. ive had it for 6+ months ran a different taurus fan and controller for a year and a half before the fan crapped out so i decided to switch to this controller works great and is easily replaced