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Bikini Bridge Inspector
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My Cherokee doesn't have any power going into the nss so my reverse lights don't work anyone have any ideas?
The WHT/PK wire is the input. The VT/BK wire is the output. The BK wire in the middle is the ground for the starter relay IIRC. It senses the park or neutral position of the tranny allowing the engine to fire up by providing ground for the starter relay.
 

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Bikini Bridge Inspector
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Ok cause I just installed a new pigtail and switch and I still don't have any reverse lights
I hesitate to ask you such a basic question, but, did you first check the 15 A brake lamp fuse in the PDC under the hood?
 

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Bikini Bridge Inspector
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I don't think that fuse would affect the BU lamps, just the brake lamps Sorry. Old brain...doesn't always function too well.
My only thought is do you have power into the WHT/PK wire when the tranny is in R? How about the output wire which is VT/BK?
If you do then I think you may have a ground problem. There are a ground wire up in the area of each front side panel.They are in each side panel area to the outside of the foot wells.
 

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Discussion Starter · #8 ·
And I looked I to it more today I used a power probe and supplied 12 volts to the violet wire and the reverse lights came back on so I think that the ecu isn't supplying 12 volts to the neutral safety switch
 

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Bikini Bridge Inspector
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I think that your problem is in the shifter assembly. I think there is a plug there that could be the problem. It gets power from a relay in the PDC.
 

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The fuse for that circuit is #20, 10a in fuse box under dash. That fuse powers other things so you would probably have additional problems if it was blown or had no power ( HVAC, flasher unit,). The switch gets power directly from that fuse so you can ignore other things like shifter, PCM etc, other than a connector or two and maybe a splice or two. If its not a fuse you will have to trace the wiring for an open circuit or loose connection somewhere
 

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Bikini Bridge Inspector
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7,386 Posts
The fuse for that circuit is #20, 10a in fuse box under dash. That fuse powers other things so you would probably have additional problems if it was blown or had no power ( HVAC, flasher unit,). The switch gets power directly from that fuse so you can ignore other things like shifter, PCM etc, other than a connector or two and maybe a splice or two. If its not a fuse you will have to trace the wiring for an open circuit or loose connection somewhere
That fuse does power that circuit then it goes through plug C103 pin #1. Pull that fuse and then check the fuse with a multi-meter for continuity. If it is god then check for power into that fuse slot. If power goes in and the fuse is good then power goes out to plug C013 pin 1. So at this point if power is there then it is after this point that your problem exists. I added yet two more diagrams.
 

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Bikini Bridge Inspector
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7,386 Posts
So, I just had a brain fart. Once you check for power at the fuse socket and insure the fuse is good, check for continuity between C103 pin #1 and the input wire in the NSS switch. If you have continuity up to that point your problem is after that point. If not then your problem is before that point..... Damn problem has to be somewhere!
 

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Bikini Bridge Inspector
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7,386 Posts
So, I just had a brain fart. Once you check for power at the fuse socket and insure the fuse is good, check for continuity between C103 pin #1 and the input wire in the NSS switch. If you have continuity up to that point your problem is after that point. If not then your problem is before that point..... Damn problem has to be somewhere!
When you got the BU lamps to work did you apply power to the INPUT side of the new NSS? If you did then the problem is BEFORE the INPUT side of the NSS switch. No voltage IN....no voltage OUT!
 

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Bikini Bridge Inspector
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Yeah I know that I applied the voltage after the connector and the lights came on so I think it's in the pcm somewhere
Go back to post #13 find plug C103 pull plug. Send 12 volts into pin #1 with the tranny in Reverse. Do you get BU lamps then?

IF you do, then the problem is BEFORE plug C103.
 

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Discussion Starter · #19 ·
So I was working on the nss again and I figured I wasn't getting any power to the tcm I applied 12 volts to the tcm fuse (was not thinking) and I am pretty sure I applied the 12 volts to the ground side of the fuse now my jeep won't start at all gauges don't work I don't hear the fuel pump kick in and it just cranks and cranks but doesn't catch do you have any ideas? I am without a vehicle and desperate!
 

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Bikini Bridge Inspector
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7,386 Posts
So I was working on the nss again and I figured I wasn't getting any power to the tcm I applied 12 volts to the tcm fuse (was not thinking) and I am pretty sure I applied the 12 volts to the ground side of the fuse now my jeep won't start at all gauges don't work I don't hear the fuel pump kick in and it just cranks and cranks but doesn't catch do you have any ideas? I am without a vehicle and desperate!
To check for input voltage for the TCM you should have used a multi-meter and pulled the fuse for the TCM and see if voltage is on one side of the fuse. To check for voltage by sending voltage through the ground circuit is not good.

What was the source of the voltage used?

That is the circuit whose fuse would get looked at first.

Then pull every other fuse in the PDC under the hood and under the dash to find out what other fuses you might have blown.
 
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