Reverse turns on running lights...

Stock FSJ Tech Area
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merrill77
Posts: 215
Joined: Fri Jul 14, 2017 6:25 am
Location: Raleigh, NC

Reverse turns on running lights...

Post by merrill77 »

and the reverse lights come on with the running lights.

'77. I just had the gauge cluster out and the steering column loosened...and was groping around alot behind there while removing and installing the cluster. So it seems likely I have caused this in the process.

Any ideas where the circuits for the reverse and running lights can come into contact with each other? Since there is a light on the gear selection indicator, I'm guessing the 77 uses the column position to turn on the reverse light? Must be in there somewhere...back to the garage...
77 Wagoneer and 97 TJ.
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tgreese
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Re: Reverse turns on running lights...

Post by tgreese »

You just have to trace it through. Use your multimeter or test light. The wiring diagram is on the Tom Collins site - that era's diagrams are quite good, IMO. If you have trouble with the wiring diagram, post up your questions. http://oljeep.com/gw/elec/GW_wiring.html

Note that these cars often develop odd electrical behaviors when the grounds fail. It would be worthwhile to clean and reseat all the lighting grounds. That may cure your problem.

Don't power up the instruments without the cluster securely in place, or without adding a ground wire from the cluster to the dash steel. I know that the CJ voltage regulator for the gauges will not work if the ground is missing, and will send full battery voltage to the gauges. The FSJ panel may be the same.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
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Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
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Phils67
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Re: Reverse turns on running lights...

Post by Phils67 »

Drop the column back down and see if you pinched the wires when you bolted it back up. The wire for the reverse may be connecting to the illumination for the gauges or indicator.
1967 Gladiator J2000, 1998 4.0L OBD2, T18, D20 twin sticks, D44HD/D60, Detroit lockers, 3.73s, 4wheel disc brake, FSSR, Dakota digital, etc.
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merrill77
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Location: Raleigh, NC

Re: Reverse turns on running lights...

Post by merrill77 »

Phils67 wrote:Drop the column back down and see if you pinched the wires when you bolted it back up. The wire for the reverse may be connecting to the illumination for the gauges or indicator.
I checked the column again (and dropped it for good measure), but cannot find any wires pinched :( Thanks, though!
77 Wagoneer and 97 TJ.
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Topic author
merrill77
Posts: 215
Joined: Fri Jul 14, 2017 6:25 am
Location: Raleigh, NC

Re: Reverse turns on running lights...

Post by merrill77 »

tgreese wrote:You just have to trace it through. Use your multimeter or test light. The wiring diagram is on the Tom Collins site - that era's diagrams are quite good, IMO. If you have trouble with the wiring diagram, post up your questions. http://oljeep.com/gw/elec/GW_wiring.html
Yeah, that is probably what I'm going to have to do :(
tgreese wrote:Don't power up the instruments without the cluster securely in place, or without adding a ground wire from the cluster to the dash steel. I know that the CJ voltage regulator for the gauges will not work if the ground is missing, and will send full battery voltage to the gauges. The FSJ panel may be the same.
Installing the cluster only uses screws through the plastic housing, so it can't provide a ground. And no voltage regulator in '77. Diagram says the cluster is grounded through the cluster connector, which is attached. But good thing to be aware of in general.
77 Wagoneer and 97 TJ.

letank
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Re: Reverse turns on running lights...

Post by letank »

merrill77 wrote: Installing the cluster only uses screws through the plastic housing, so it can't provide a ground. And no voltage regulator in '77. Diagram says the cluster is grounded through the cluster connector, which is attached. But good thing to be aware of in general.
Correct, there is a ground coming thru the multiple "molex round connector" and a separate wire for the heater panel, but it is a good idea to add an extra ground wire from the fat cluster circuit board screw to another convenient place, either the courtesy light ground, or a loop to the heater control ground.

As for the reverse being on... I am off site, no access to my TSM.

Remove one light bulb at a time, a shorted ground on the BU housing could be the culprit.... I had one on the front blinkers that created a dim blinker indicator for years until I decided to swap one blinker housing, upon testing I could not find anything wrong.

Or you can suspect that the gear shifter might be binding something in the engine compartment by the firewall.
Michel
74 wag (349 Kmiles... parked, next step is a rust free body)
85 Gwag (229 Kmiles... the running test lab)
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