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CJ5 AMC360 Ford Taurus 2 speed fan wiring

D_JEEPER

D_JEEPER

Picked the wrong week to quit sniffing glue
Joined
May 21, 2020
Member Number
870
Messages
747
Currently running howell efi but I do not think the Howell does any fan control, unfortunately.
Currently on the jeep there is a non-weatherproof mechanical temp sensor/probe that has seen better days. It was somehow wired in with 2 relays that would definitely not be enough for the high draw. It all needs to be ripped out and redone a little better....especially since it does not work anymore :homer:
I am looking at the Volvo relay option right now. I like it all together like that. Would just need to get the connectors with it haha. (Anyone have a source?)
Volvo_relay.jpg

However if someone out there already has a solution for the whole wiring kit, I wouldn't mind turnkey....depending on the convenience charge tacked on lol. The hard part comes in with the 2 speed functionality of the fan. Kick on low at 180 and high at 200 or something like that. Testing the jeep in the shop, it seemed to hold 180 fine with the LOW hardwired on... but it is also like 40 degrees outside and not under load.

Anyone run a 2 speed thermal probe on their CJ? Thoughts on where that would go? I currently have the water temp sensor on top of the thermostat housing....so that spot is taken.
 
There is a coolant crossover in the front part of the intake manifold that you can tap into unless there is a vacuum switch still there.
 
I got one of the Volvo relay setups on eBay with a harness recently. Seems to work fine
 
MigGunslinger said:
There is a coolant crossover in the front part of the intake manifold that you can tap into unless there is a vacuum switch still there.
Click to expand...
Ah ok that is good. I have an Edelbrock intake manifold so I will have to check out what is going on there. I do see a plug with some sealant so that one might be the one I tap into.
Bebop said:
D_JEEPER
www.therangerstation.com

Volvo Electric Cooling Fan - The Ranger Station

Looking for an electric fan option to cool your radiator? The 2-speed Volvo fan and relays have become a popular swap. The fan you need is from a 1990’s Volvo 740, 850 or 950 sedan or wagon. The 940 fan … Continued
www.therangerstation.com
Click to expand...
Well, I already have the cooling fan from a Taurus that runs both low and high speeds when hardwired so I would probably stick with that one for now :grinpimp:
_stucky said:
I got one of the Volvo relay setups on eBay with a harness recently. Seems to work fine
Click to expand...
Good deal, I went ahead and ordered one of those with the plugs and everything. I also ordered a 75A relay to go upstream from all of this to be switched by either a dash switch or a key-switched circuit somewhere.:beer:
 
volvo_relay_diagram (2).jpg


Couple small changes to a diagram I found online but I figure this would be the route I go. Still need to look into that manifold plug I suspect is the coolant crossover.
 
I actually did this very thing haha. I went out to the site and looked haha
Thank you. That was the plug (as well as the one on the other side) that I was thinking about.
 
So I plan to run 8 or 6ga from the battery to the relay and from the relay to the Volvo relay. I plan to have these on the firewall and run the fan wires down the grill support with the rest of the loom.

From there, does anyone know what the factory wire gauges are for the volvo relay? With the surge of the high speed (my biggest concern) I just want to make sure I get these things right.
 
D_JEEPER said:
Well, I already have the cooling fan from a Taurus that runs both low and high speeds when hardwired so I would probably stick with that one for now :grinpimp:
Click to expand...
Volvo and Taurus fans are the same.
That's why I gave you the link
 
Bebop said:
Volvo and Taurus fans are the same.
That's why I gave you the link
Click to expand...
Ah ok. Well thanks then :flipoff2:

Dropped the coin on all of the things I would need to get this project done except for the relay bracket. Im just going to make something haha.

I am running 10ga to the fan motor from the relay, 8ga for the short run of power leads from the battery. I picked up the BMW sensor . I went with the 80/88C since the 360 wants to run hot otherwise and my thermostat is 180*. I feel like 190 is when things start to really take off under the hood so that would be a good temp to kick up to high speed.

I decided to go with one of those in-line thermostatic sensor housings. The Howell EFI uses the one near the oil fill tube and the CJ gauge uses a sensor on top of the thermostat. Reading some opinions online it looks like the radiator hose location is preferred since you aren't kicking on the fan based on engine temp but rather coolant temp so that you aren't cooling potentially already cooler coolant :grinpimp:

I am fairly excited to do this because I feel like it will clean up and consolidate some of the bundled wire loom under my hood. It will also let me break out my radiator fan wires from my main loom for future troubleshooting, if need be.:homer:
 
OK, Finally got the chance to get back out to the garage and finish this little project (mostly).

So I measured my radiator hose and it was 1.5" so I ordered a 38mm in-line thermostat housing. Well, turns out that the china company measured the raised rib on their housing at 38mm, not the shank of the tube, which was like 35mm. Well, that is just too loose for comfort with a 16lb rad cap lol. That was one of the big setbacks, since around Christmas/New Years the mailing system is over-saturated and delayed.
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:homer::shaking:


BUT, I finally received all of the other pieces and began the daunting task of wiring. I built the wiring harness for the Taurus fan using 10ga wire to match the factory size. I had to decipher and tap into a switched power source on the Painless Wiring harness.

One of my rainy month projects will be to repackage the wiring harness and clean it up a bit... but for right now it is bundled and out of the way haha.

For this, all connectors were crimped, soldered and heat-shrunk (shrank, shrinked, shrank-ded?).
I picked up a 75A Bosch relay and mounted it on the firewall I ran a 10ga wire from the positive terminal to a 75A fuse block and then from there to the load input side of the relay. Then I simply put a connector on the Volvo relay power connector (10ga as well) and connected that to the Load out side of the Bosch relay. The sensor wires were like 20ga so I ran those to the BMW 2 speed temp sensor on the in-line radiator hose housing. Green is low speed, Purple is high speed and Black is ground, which was ran over to the coil mounting bolt on the intake manifold.

With everything set up and what not, I started the jeep and let it get up to temperature. It surpassed 180 and continued past 210 until it hit 235 and the fan finally kicked on...however it was on the HIGH speed, not low speed. On HIGH, it brough the temps right back down to 180 within a minute or so because that thing really moves some air haha.

I did this a few more times before deciding that the switch was faulty because it never kicks low speed on, only high. I jumped the connector wires to verify that low speed does in fact work as it should. With the temp sensor being a 80*C/88*C, it should kick low fan on around 180ish and then high comes on around 195 (accounting for temp response time delays). What is strange is high speed will continue until the temp drops to like 178ish on the thermostat and then the fan shuts off.:mad3:

Anyways, the wiring is functioning it seems... just need a good sensor:homer:
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Does the low speed fan relay ground through the temp sensor?

You've electrically isolated the sensor by putting it inline in the hose.
 
We noticed a bit of a delay with those switches, also with the contour fan once it got hot the high speed was always on and the thermostat regulated temp.

You can also isolate the switch and test it in a pot of water.
 
arse_sidewards said:
Does the low speed fan relay ground through the temp sensor?

You've electrically isolated the sensor by putting it inline in the hose.
Click to expand...
The wiring is 3 connectors. High, Low and Ground. The Ground is connected back to the intake manifold on the coil mounting bracket. I tested the wiring manually. Plus since the high speed kicked on just fine, it seems to be wired up ok. Just no low speed.
 
MigGunslinger said:
We noticed a bit of a delay with those switches, also with the contour fan once it got hot the high speed was always on and the thermostat regulated temp.

You can also isolate the switch and test it in a pot of water.
Click to expand...
I have a replacement coming and if I see the same issue, I am going to get scientific up in this shit LOL.
I mean, as it is now, I would not overheat on the trail, but it would regulate better if low came on when it was supposed to haha
 
1704735881319.png


I did this so you didn't need another high power relay to power the Volvo high-power relay. You can also wire the relay (relays in this case for reach circuit) to interrupt the wire from the temp switch to the Volvo relay if the switch isn't isolated from ground.
 
MigGunslinger said:
We noticed a bit of a delay with those switches, also with the contour fan once it got hot the high speed was always on and the thermostat regulated temp.

You can also isolate the switch and test it in a pot of water.
Click to expand...
I mean, I understand a 'bit' of delay, but when the temps go from 180 to 235 over the course of a few minutes, I would imagine a 180 degree sensor to kick on low at some point haha. I am ok if the 195 temp for high speed take a smidge longer but if the low speed would kick on it probably wouldn't even need that one.


Also to note, with the low speed side of the switch I had no continuity when the high speed was going.
 
D_JEEPER said:
I mean, I understand a 'bit' of delay, but when the temps go from 180 to 235 over the course of a few minutes, I would imagine a 180 degree sensor to kick on low at some point haha. I am ok if the 195 temp for high speed take a smidge longer but if the low speed would kick on it probably wouldn't even need that one.


Also to note, with the low speed side of the switch I had no continuity when the high speed was going.
Click to expand...
I don't remember the numbers exactly but I remember watching the temps climb and climb being worried until the fans finally came on:laughing:

Also your switch is on the radiator side of the thermostat which should read cooler than the engine until the thermostat opens up, that could be adding to your delay.

Agree that it sounds like a bad switch.
 
MigGunslinger said:
I don't remember the numbers exactly but I remember watching the temps climb and climb being worried until the fans finally came on:laughing:

Also your switch is on the radiator side of the thermostat which should read cooler than the engine until the thermostat opens up, that could be adding to your delay.

Agree that it sounds like a bad switch.
Click to expand...
Yeah, I put it on the radiator side. I did some reading and someone had a writeup about wanting your fan to operate off of radiator temps so you aren't unnecessarily cooling if you are reading off of engine temps. The thermostat is a 180 degree so that is kind of my baseline. I do notice that the water temp gauge reads and holds a consistent 180 when the fan is on so that indicates my sensor, located on the top of the thermostat housing, is (most likely) good.

I feel like the delay in low speed would be ok if the water temps got up to 190-195 before the fan kicked on low to regulate. But yeah, I was sweating a little when it hit 235.... so much so I jumped when the fan did kick on. I've had a radiator hose let go at high temp before so I'm a bit twitchy with that particular source of potential energy haha.
 
Once everything gets nice and hot it all kind of evens out but it's going to take time until you trust the system is working the way you want it.
 
D_JEEPER said:
Yeah, I put it on the radiator side. I did some reading and someone had a writeup about wanting your fan to operate off of radiator temps so you aren't unnecessarily cooling if you are reading off of engine temps. The thermostat is a 180 degree so that is kind of my baseline. I do notice that the water temp gauge reads and holds a consistent 180 when the fan is on so that indicates my sensor, located on the top of the thermostat housing, is (most likely) good.

I feel like the delay in low speed would be ok if the water temps got up to 190-195 before the fan kicked on low to regulate. But yeah, I was sweating a little when it hit 235.... so much so I jumped when the fan did kick on. I've had a radiator hose let go at high temp before so I'm a bit twitchy with that particular source of potential energy haha.
Click to expand...
What about switching the high/low temp wiring to make the high speed fan kick on with the low speed temp? If the high speed fan kicks on it tells you the temperature sensor is okay. If you get above 235 and no fan kicks on you’d know it was the fan.
 
RunningProblem said:
What about switching the high/low temp wiring to make the high speed fan kick on with the low speed temp? If the high speed fan kicks on it tells you the temperature sensor is okay. If you get above 235 and no fan kicks on you’d know it was the fan.
Click to expand...
Wouldn't switching the wiring around just cause the low speed side to kick on when it hits that high temp 2nd speed threshold?
In the video I posted, I tested the wiring by jumping Low speed to Ground on the plug, and then High speed to Ground on the plug. Both of those work.
 
arse_sidewards said:
i.e you are testing the low speed side of the fan/relay system.

If it works, great, your temp sensor is the issue.

If not, then your fan/relay system is suspect.
Click to expand...
See video in post #15 :laughing::flipoff2:
 
D_JEEPER said:
Wouldn't switching the wiring around just cause the low speed side to kick on when it hits that high temp 2nd speed threshold?
In the video I posted, I tested the wiring by jumping Low speed to Ground on the plug, and then High speed to Ground on the plug. Both of those work.
Click to expand...
yes. It’s just another way to confirm it since you said you tested the fan wired the way you want it, and you showed the fan works when 12 volts are sent to the low speed fan.

Maybe some magic would happen and the low speed won’t kick on at 235 when the wiring is switched around and you have a bad relay in your Volvo fan relay.
 
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