Odd, question, I need the wiring diagram for a dodge caravan

[JeepsAndGuns]

Might seem like a odd question, but I am in need of the wiring diagram that shows the raditor fan on a 93 dodge caravan.
I went to the junkyard with a tapemeasure and found a electric fan from a 93 dodge caravan with a V6 and it fits the measurements of the radiator on my cherokee almost perfectly. Its apparently a 2 speed fan, but it has 4 wires. Black, yellow, dark green, and light green. If I could find a factory diagram showing where each wire from the fan goes, that would be awesome! I have been searching google with no luck yet. Hoping maybe some of you guys might have some more resources than I do.

[RobertISaar]

i hate chrysler diagrams... so difficult to read compared to what GM and Ford were doing in the same era.

http://i.imgur.com/0jSrp.png

looks like yellow and black are grounds, so the greens are the positive voltages. can't tell which ones are paired though.

i'd test it in the junkyard with a portable jumper pack.

[JeepsAndGuns]

I played around with it when I got home yesterday, and found hig and low speeds, but was confused by the combination of wires to do so.
Ground the black wire, apply power to light green, fan runs, remove power from light green and switch to dark green, fan runs, appears to be the same speed. keep DG hooked up and add power to LG, fan speed picks up slightly, but just enough to notice. Found by accident that the yellow was another ground, it kinda touched the valve cover when I wasnt watching and had both greens and the black hooked up. When the yellow found ground the fan took off like a airplane...lol
I just wanted to know what the proper or factory way was to wire it up, as I didnt want to burn it up.

Any more of that diagram? Where does the dark green go? It shows the ground, then the light green and yellow are both hooked to relays and it turns on the relays at the same time to give the motor extra power and ground for high speed. But what about the low speed? Does the DG come from a relay too, or is it a switched power wire and low speed run anytime the ignition is on? And also, I wonder if it removes power from the low speed wire when it turns on the high speed, or leaves it on.

[RobertISaar]

i have no idea what the answer is to any of those questions is. chrysler provides so little information and broken diagrams that i can't really tell.

it actually sounds like you can have either one circuit connected for low speed, then both connected for high speed.

[JeepsAndGuns]

it actually sounds like you can have either one circuit connected for low speed, then both connected for high speed.

Kinda what I was thinking. But was just curious where the dark green wire went to.
Guess if I burn up this one I just go back to the junkyard and grab another one. Only paid $13 for this one...lol. Gotta love pull a part junkyard.

[RobertISaar]

i ASSUME directly to either the battery or some other high amperage capability power distribution center.

but i'll never know. from alldata, these diagrams are just total crap. maybe it was better in the FSM, but i've never used them.

[jim_in_dorris]

Just talked to my son, he's a level 3 chrysler tech at a dealership. He said that the yellow wire reports the fan speed back to the PCM. So black is ground, Lt green and Dk green are fan power, and the yellow wire is a sensor that reports fan rpm back to PCM.

[RobertISaar]

they use a 12 guage wire for fan speed sensing????

and that yellow wire is connected to ground via a relay....

[JeepsAndGuns]

Thats what I was thinking, that large of a wire for senseing? And that diagram shows it going through a "high speed fan ground relay". And clearly labels the wire as ground.

[EagleMark]

Sounds more like a PWM speed control then speed sensing? You may have found the PWM relay we were looking for?

[TruckinGeek]

Perhaps this will help.3157

[RobertISaar]

that's a hell of a lot better than what alldata was showing....

looks like the dark green and black circuit is used for low speed operation.

then two relays are used to switch on high speed ode via the light green and yellow circuit....

how very odd. i don't see why it couldn't be done with just two relays(for the positive sides).

interesting that the PCM can control either, but it seems if PCM control fails for whatever reason, the temp switch in the radiator can force on the relays used for high speed usage...

[JeepsAndGuns]

Thanks truckingeek!
Now to get it mounted, relays and wires ran, and do the $0D fan mod :D

[jim_in_dorris]

He said definately that if the yellow wire is 12 gauge, then it is NOT a sensor wire to the PCM. It really looks like the diagram is correct.

[TruckinGeek]

Your welcome, glad I could help for once.

[Jesse***]

Hello folks, I just signed on here to have a look at the Caravan wiring diagram. Thanks for posting that btw! I too came home from the junkyard with a two speed Caravan fan to repurpose, but was scratching my head why the grounds were separated.

In fact I'm still scratching my head why the grounds are separated, when the fan is running on low and if the high ground is grounded, what is the effect? I suppose there will be induced voltage on the high speed wire, maybe that induced voltage goes to ground if grounded and power is wasted? Any EE's among us....

Did you bother with the high speed ground relay? Or just ground them both and make do with two power relays, one for each speed? Actually I've about talked myself into isolating the ground like Crysler did, but it'd be great to hear other opinions.

thanks
Jesse

[JeepsAndGuns]

I actually ended up not using this fan. My measurements were off and it ended up being too thick, it would hit the water pump pulley on my engine.
Sorry I couldnt be of more help.

[Jesse***]

Well thats too bad, I thought that was one of the narrower ones in the junkyardf. Since I don't understand the logic, I"m just playing it safe and running the extra relay.