No [P] or [N] indicator - neutral safety switch perhaps?
#11
02-18-2013, 10:50 AM
Hi Pete,
Sorry, have not done any further diagnosis. I've been busy and it went on the back burner... Truck runs and shifts normally. Can go into and out of 4WD Hi (good thing in the recent snowstorms...). Still have no indicator lights for P and N and lately, if I shift down to 1, the indicator light stays on 1 even when shifting up to 2 or 3. The transmission shifts, but the indicator sticks.
If I shift up to 3 from 1, the 3 will eventually illuminate, but it doesn't change right away. D lights up normally, as does R. Haven't tried 4WD low lately... It was working back when I first posted, but that was a few months ago. Will try it tomorrow. The transfer case control module needs to know that the transmission is in neutral before shifting into 4WD low.
Sorry, have not done any further diagnosis. I've been busy and it went on the back burner... Truck runs and shifts normally. Can go into and out of 4WD Hi (good thing in the recent snowstorms...). Still have no indicator lights for P and N and lately, if I shift down to 1, the indicator light stays on 1 even when shifting up to 2 or 3. The transmission shifts, but the indicator sticks.
If I shift up to 3 from 1, the 3 will eventually illuminate, but it doesn't change right away. D lights up normally, as does R. Haven't tried 4WD low lately... It was working back when I first posted, but that was a few months ago. Will try it tomorrow. The transfer case control module needs to know that the transmission is in neutral before shifting into 4WD low.
I got mine fixed! I found a bad wire at the module in the kick pad on the passenger side, but that still did not fix what I had going on. So I when back to the neatural Saftey switch. Then one that I put on when I bought the truck! Because it was bad at that time, I also had to replace both plugs. So I checked to make sure that I had wired it right an I had so I got a new switch from carquest and put it on to see what would happen and bam. The park light and neatural work now so the new switch I bought two years ago was no good right from the start! So now the T case works fine so if I was you and everything checks out with the wiring I would buy a switch.
Good luck Pete
#12
02-20-2013, 08:25 PM
Hi Pete,
That's good to know. I suspected the switch from the start. My truck does go into 4WD low though... so my problem is a bit different from yours. The module in the kick pad on the passenger's side is the transfer case control module, so maybe you had 2 separate problems.
In any case, a new NSS is only around $25. so I will replace it when the weather warms up a bit. Unfortunately, I don't have a garage and it's 22º outside...
Thanks for the input!
That's good to know. I suspected the switch from the start. My truck does go into 4WD low though... so my problem is a bit different from yours. The module in the kick pad on the passenger's side is the transfer case control module, so maybe you had 2 separate problems.
In any case, a new NSS is only around $25. so I will replace it when the weather warms up a bit. Unfortunately, I don't have a garage and it's 22º outside...
Thanks for the input!
#13
07-26-2017, 09:25 AM
Problem Fixed!!
I know this is an old thread, but I just had the same exact problem with my 4.3 02 S10 not lighting up the P and N on dash.
The 4l60e transmission pnp switch is not the problem. The issue is a ground or lack thereof. The safety switch uses different combinations of open and closed circuits to tell the dash which gear it is in, and it's done through the four wire (C1) harness. If the safety switch isn't receiving a ground, it will still function normally, but the dash output won't work without engine running. When running, the ECU tells the dash which gear it's in from the internal pressure switches inside transmission. However, if vehicle isn't running but key is on, nothing lights on dash.
The fix is amazingly simple. On the 7 wire (C2) harness, there is a black/white wire coming off of the D (Google the plug diagram) slot of the harness. If looking at the plug with the four slots on top and the three slots on bottom, it is the top far right slot. Use a ohm tester to check continuity on this wire. If it does not show zero ohms, your safety switch is not grounded. I remedied the issue by simply cutting the black/white wire and splicing a new wire to it and grounding it directly to the bolt that holds the safety switch to the transmission, and it works like a charm!
I hope this helps anyone who comes across this thread again who has this exact same issue because this is only thread I could find after hours of searching that described my problem to a tee.
The 4l60e transmission pnp switch is not the problem. The issue is a ground or lack thereof. The safety switch uses different combinations of open and closed circuits to tell the dash which gear it is in, and it's done through the four wire (C1) harness. If the safety switch isn't receiving a ground, it will still function normally, but the dash output won't work without engine running. When running, the ECU tells the dash which gear it's in from the internal pressure switches inside transmission. However, if vehicle isn't running but key is on, nothing lights on dash.
The fix is amazingly simple. On the 7 wire (C2) harness, there is a black/white wire coming off of the D (Google the plug diagram) slot of the harness. If looking at the plug with the four slots on top and the three slots on bottom, it is the top far right slot. Use a ohm tester to check continuity on this wire. If it does not show zero ohms, your safety switch is not grounded. I remedied the issue by simply cutting the black/white wire and splicing a new wire to it and grounding it directly to the bolt that holds the safety switch to the transmission, and it works like a charm!
I hope this helps anyone who comes across this thread again who has this exact same issue because this is only thread I could find after hours of searching that described my problem to a tee.
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