mississippi
New member
my electric fan will not cut on. i have changed the relay in the pdc and it still will not cut on i can use a jumper wire on the relay and it will start. any idea on where to look for a short at
electric fan
- Thread starter mississippi
- Start date
SteelHeadz
Super Moderator
Welcome to Jeepz.. What model Jeep do you have that has this issue?
mississippi
New member
1997 jeep cherokee 4x4 4.0L
SteelHeadz
Super Moderator
Wiggle the harness to the PDC and see if the fan kicks on intermittently. Here's a couple of wiring Diagrams. Looking at the Schematic diagram, it looks like the internal ground to the PDC could be at fault but this would have to be verified by you. From what you said, by installing a jumper wire on the relay plug on the PDC turns on the fan, means that the relay is not energizing. There is also a Fusible link that runs from the relay to the alternator circuit, make sure thats good along with the 40 amp fuse in the PDC..
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what i did on my xj. after fighting overheating issues ( new raditor, hoses theromstat, and water pump.) still over heated. i just wired the electric fan to a relay and a switch on the dash. i just turn it on when i start the motor and when im wheeling i leave it on for 10 or 15 minutes after i turn the motor off helped the temp stay where it should. my friend did the samething but wired it to a switched 12v power point so it come on automaticly when he turns his key on.
Ok so i have a 03 grand cherokee inline 6. i have a simular problem. i went on a trip about 2 1/2 hrs and i get off the interstate and once i do the temp gauge goes to about 230. i quick made it to a parking garage and parked it. when i was ready to leave i made it about 60 miles before i got to my parents house. I figured it was the fan motor. It wasnt. the fuse is good and when i turn the AC on i can hear a click like the fan trying to turn on but it doesnt. i am thinking relay and i am looking for more advice.
Is my wiring diagram the same as the one above?
Is my wiring diagram the same as the one above?
SteelHeadz
Super Moderator
Nope, the GC's relay is located under the passenger headlamp and housing. the best way to service the relay is to remove the passenger headlamp then cut a square access hole to reveal the relay. There are 2 screws holding the relay to the body. Remove the screws then carefully retrieve the relay and disconnect the electrical connector. dont let the connector go back in the hole until you plug in the new relay. Before you install the new relay, apply a small amount of dielectric grease on the bottom of the relay. Most often the relay is all needed to fix the inop radiator fan but sometimes the fan module is also inop.Heres a diagram for your GC.
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SteelHeadz
Super Moderator
No, there is no other fuse exept the one on the PDC, 40 amp, fuse # 10. Using the schematic diagram, with the relay still connected, run a jumper from the gray wire to the dark green wire using a large paperclip. DO NOT use your finger to hold the jumper, instead use a small plier. (Dont ask why) . With the engine running and A/C on and jumper in place, the fan should turn on.
SteelHeadz
Super Moderator
The other way to replace the relay would be to remove the grill and front Facia/ bumper assembly. Disconnect the negative battery terminal and wait 15 mins. before proceeding.The hole cutting is a lot easier and will only be a one time deal. This will make it easier to service in the future. After you remove the passenger headlamp, there will be a slit on the plastic. Place a light on the underside of the plastic so you can see the placement of the relay. This will give you an idea where to cut the hole. You can either use a hole saw or a cutting wheel to make this access hole. This hole will NOT be visible when the headlamp is reinstalled later so dont worry too much. Avoid extending the cutting tool too far past the thickness of the plastic to avoid cutting into something underneath by accident.
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ok so i just took the relay out. I cant seem to find a way to get to the wires without stripping them a bit so i can jump them. I have attached a volt meter to the relay and there is no conduction between any of the four prongs regardless of configuration. I also tried grounding it and checking with the volt meter.
Does this mean it doesnt work or am i wasteing my time?
Does this mean it doesnt work or am i wasteing my time?
SteelHeadz
Super Moderator
Key on, engine off. Check for battery voltage from the gray wire and ground. If there's no voltage found, check the #10 fuse on the PDC. If the fuse is good, but still no voltage, the problem will be in the PDC. IF there is battery voltage from the gray wire and ground, from the back of the relay connector , backprobe a jumper between the gray and the DARK green. do not remove the relay as you do this test, otherwise , the fan module will loose its path to ground. IF the fan still did not turn on and you have voltage on the gray wire and ground, with the jumper still in place, Tap the radiator fan and see if the fan intermittently kicks on. If so, you have 2 problems, Relay and Fan module. I've seen it happen but rarely.
Ok i just want to say. I am back in bussiness. It was the relay and i am glad to say it wasnt that hard of a job to do. to ease my own issues i even siliconed the plastic right back in its place. cost me 40 bucks for the relay and .45 cents for a screw that i lost when i went to put it back in. thanks steelheadz
SteelHeadz
Super Moderator
I'm glad you fixed it. See , that wasn't too bad, although, the relay should have come with 2 new screws.
well no screws where in the box. the only thing was the electric grease. No big deal i can walk to the hardware store from my house so didnt matter to me. the only thing i notice now is it sound like there is an arking noise coming from the drivers side of the engine when i start it up. idk what it is nor can i find anything wrong or any wires bare or arking when i look at it.
SteelHeadz
Super Moderator
Have someone start it up for you while you look for the noise. Just be sure to keep your hands away from the moving parts under the hood.
Hello, I am new to the group and currently drive a 1997 Cherokee. A day or so ago my electric fan stopped shutting off with the engine. I came home tonight and an hour later it was still on. It did (obviously) turn off when my husband disconnected the "main electrical feed" (as best as I can understand what it is). A friend of ours suggested finding the "Thermocoupler". I have been scouring the internet and can not find any diagrams that tell me where the "Thermocoupler" is.
BTW, the plug that my husband unplugged feeds directly from the fan and has a red "button" on the piece that it plugs into. The dash does not indicate overheating or any other obvious problems. I hope that someone can help soon.
Thanks
BTW, the plug that my husband unplugged feeds directly from the fan and has a red "button" on the piece that it plugs into. The dash does not indicate overheating or any other obvious problems. I hope that someone can help soon.
Thanks
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