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Kevin, Owner Kevins Mobile repair Atlanta
Category: Jeep
Satisfied Customers: 308
Experience:  14 years dealer trained, Master Electrical,AC,Body Mechanical, Drive ablity.
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2000 jeep grand cherokee: relays..check engine light...ignition switch

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2000 jeep grand cherokee inline 6.While trying to hard wire a switch to turn on the radiator fan a friend of mine poked a wire to see if it had juice at key on position.From the driver seat i heard a pop.All the fuses and relays are good still,but wont start unless i backfeed juice from the battery to the wire he was poking.When i engage the switch i put in it turns on the fuel pump(i can hear it turn on)and the fuel guage and the truck run fine except for the check engine light.I have replaced the ignition switch no help.Can anyone help with this problem?

Welcome to teh site my name is Kevin

go back and chk all the fuses and for god sake dont let him monkey with the fan any more replace the relay for the fan for 80 bucks and U wont have this kinda issue again.

The fuses under the driver sai dash there are a few there.

Which wire was he poking ne way?

Customer: replied 8 years ago.
I think it was the fuel pump wire in the harness located in front of the pcm,not the wires connected to the pcm.The floating harness that runs underneath the PDC

why would he mess with the fuel pump wire for the fan?


fuse 12 10 amp is for the fuel pump under the driver side dash

Customer: replied 8 years ago.
He wanted to have the fan turn on when i turned on the truck.All the fuses are good ive checked all of them many times ive been driving the truck for 6 months like this but inspection comming up need to get the check engine light off.Its been on a code reader and it throws codes 0130,0136,0443,1687 like i said the truck runs fine with that backfeed through that wire
what wire color was it?
Customer: replied 8 years ago.
orange and dark blue

that wire is for the control side of the fuel pump. the power supply comes from teh IGN switch to a fuse 12 10 amp under the driver side dash then to the fuel pump and also goes to the PCM. so my susgestion is to trace it from teh ign switch to the fuse then from teh fuse to the fuel pump relay then to the pcm see if u have a brunt up wire ,blown fuse or burnt up ign switch connector.

tell me again u have checked the fuses under the hood and dash? how are u looking at them with a test light or pulling them out?

Customer: replied 8 years ago.
Ive checked them both ways in both locations.Ive also changed the ignition switch it was only 35 bucks so i figured ill try it no change.I also took it to a local certified mechanic,he said it had something to do with the auto shutdown relay circiut and i should take it to the dealer.Could something have happened to the pcm?

U said it runs when u add power to the wire that wire is just power to the fuel pump relay and IGN switch feed to the pcm if they had gotten damaged from it it would not run regardless if u add power to it or not. It is also part of the ASD control.

Here is the down and dirty U dont have power on a wire that should have power when u turn the ign switch on start at the switch with a test light or volt meter and back prob see if U have power at the ign switch on the same orange and blue wire

Customer: replied 8 years ago.
And if ther is no power at the ign switch when the key is on what then?

power for it comes from a 40 amp fuse under the hood

there is a simple explnation for this I just need to know things are being done right over there

Customer: replied 8 years ago.
Im no electrician thats for sure.And it is 1130 pm right now and i cant do any tests.Do you think i should just run new wire the whole way from the ignition switch to wherever that orange and blue wire runs?Or would the placement of the feed wire i installed give an indication of where the short is?Also i just remembered my mechanic saying something about one leg of the fuel pump relay in PDC having no juice until i hit the switch.I have a haynes manual and it looks like the fuel pump relay and the asd relay are connected could that be the spot?
I would start with the ign switch chk for power there and then trace back to the fuel pump asd side. U have a wire diagram if not use this one graphic
Customer: replied 8 years ago.
So basicly take a test light and check for power at the ign switch then for power at the fuse box inside then at the box under the hood anywhere else?And if i find no power at any of these points replace the wire itself?
chk that part first then get back to me tommarow
Customer: replied 8 years ago.
Hows that work first time on this site do i accept and pay again tommorow?
no there is only one accept time it will stay open until it times out no activity
Customer: replied 8 years ago.
Of course its raining today and i have no garage to work in.I will try to check it out tuesday morning.I thank you for your paitence and i promise i will accept your answer so you get paid for your time.I feel like we are zeroing in on the problem.What is the fix if there is no power at the ignition switch?
a 40 amp fuse or a wire from the fuse to the ign switch
Kevin and 6 other Jeep Specialists are ready to help you
Customer: replied 8 years ago.
Hey man youve done it.Great help all is fixed.I tested everything and all was good, got confused,decieded to go over the fuse panel AGAIN sure enough found a blown fuse replaced it everything works.Im really thankful for your help,and will refer you to everyone that has any jeep/chrysler problems.