'98 K1500 Reverse light on in 'Park'

[skillguy]

Hi all,

Last year I had to put a reman. transmission in my truck ('98 K1500 ext cab, 5.7L, don't remember the transmission model #). An out-of-town shop did the work because that's where the truck died (not my favorite way to find a shop). Since the repair, the reverse lights are only on when the truck is in 'Park.' They do not light in 'Reverse' or any other gear. I tried to adjust the module that is attached to the shift linkage where it goes into the transmission housing (sorry, I don't remember the technical name for this part), but it wouldn't move enough to correct the problem.

Any ideas about how to correct this issue?

I'm a little embarassed to call the shop a year after they did the work to ask about a problem.

Thanks in advance,
Chuck

[taillight]

The backup lamp switch is on the left side of the transmission below the shift tower. I don't think it is adjustable but check it. It might have to be replaced.

[skillguy]

I'll take a look under there tonight and report back.

Thanks,
Chuck

[Jeremy-WI]

Can you start the vehicle when it has the backup lights on? That switch on the side of the tranny is also the neutral safety switch and also lights up the corresponding gear on the PRNDL. Does the shifter work correctly as far as neutral being neutral on the tranny and low on the shifter is low for the tranny? I know there is some adjustment possible on the shift cable if the shifter and tranny aren't corresponding

[skillguy]

The truck does start in 'Park' with the reverse lights on, and everything jives between the shifter and the transmission.

We got rained on last night, so I will try to take a look under the truck tonight and report back. I will follow the routing of the shifter cable and see if I can make any corrections there. I hadn't thought of that approach.

Thanks,
Chuck

[skillguy]

Alright. It took a while , but I figured it out! Essentially, two wires got crossed at the park/neutral switch when I had the transmission work done last year. Here are the details:

I adjusted everything I could think of but nothing worked. Besides, all the other functions worked just fine (park/neutral start lock, PRND321 indicator, etc.). Out of desperation, I looked at the wiring diagram for the park/neutral switch. When I had the transmission work done last year, the shop must have replaced this switch because its wiring harness has also been replaced. The wire going to the reverse lights is supposed to be light green. When I looked at the harness, there were TWO light green wires. After some volt meter work, I realized that the second light green wire goes to the brake pedal interlock (won't let you shift out of park without depressing the brake), and more importantly, the two green wires were switched! I clipped and reversed them, and everything works perfectly (including the brake pedal interlock which I never missed!).

Thanks again for your input,
Chuck