Reverse Lights Not Working
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4wd Low
Joined: May 2026
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Ok I’ve made some decent progress today. Dave those two photos you shared earlier are starting to click with this caveman.
I have a similar harness of which that “mystery connector” comes out along with a wire that runs to the rear tail lights.
I tested the other day in RUN and wasn’t getting any voltage in the terminals of the mystery connector. I’m wondering if that was plugged into another transmission this truck might have had at some point.
Additionally, I’m wondering if the feed is dead further upstream. The wires don’t look the greatest.
I checked the fuse and it was good.
is there some other test I can do in front of the connector? If it’s just the connector, do I clip that off and run the new plug into the switch to this? I’ll do some research tonight.
thank you. Learning a lot!
Lead Driver
Joined: Apr 2002
Posts: 5,265
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Did you check the door tag to see which transmission was built into your truck? Once you know the build the wiring will be the same then look up the switch for the original trans. The switch will tell you the connector type. Which should be a two wire coming off the frame harness. Now it could have been modified along the way as well. Look for cut and paste scars.
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4wd Low
Joined: May 2026
Posts: 14
Likes: 0
Did you check the door tag to see which transmission was built into your truck? Once you know the build the wiring will be the same then look up the switch for the original trans. The switch will tell you the connector type. Which should be a two wire coming off the frame harness. Now it could have been modified along the way as well. Look for cut and paste scars.
Lead Driver
Joined: Apr 2002
Posts: 5,265
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I'm pretty sure the T19 and the T18 have the same reverse switch. Look up part numbers for both on rockauto.com. the shape is the same oval, so you're still looking for that oval connector.
FTE Legend
Joined: Nov 2015
Posts: 30,860
Likes: 4,106
From: Angier, NC
Did you check the door tag to see which transmission was built into your truck? Once you know the build the wiring will be the same then look up the switch for the original trans. The switch will tell you the connector type. Which should be a two wire coming off the frame harness. Now it could have been modified along the way as well. Look for cut and paste scars.
So that tells me the frame harness from the main to the plug I showed and then to the rear lights would be the same too.
You need to find what wire in the frame harness that goes to the rear backup lights. Is it 1 of the wires in the 4 wire plug?
All you need to do it put power to that wire for the lights to work.
That is why there is power going to the switch and then out to a wire going to the lights out back.
It is that simple.
Maybe pull 1 of the rear lights and see what the wire color is to the backup bulbs and see if that color is 1 of the 4 at that plug.
Then all you have to do is get power to 1 side of the switch and out to that wire to the rear.
Dave ----
Lead Driver
Joined: Apr 2002
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Besides pulling a reverse lamp out to check the wire color you can also look at the EVTM for your year over on Gary's site. Did Max post the link? He has been Johnny on the spot with those handy links lately.
Lead Driver
Joined: Jun 2013
Posts: 5,650
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From: Tolland, CT
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