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M38a1 turn signals

Posted: Tue Mar 08, 2022 12:01 pm
by Shug4
Has anyone ever changed the rear light on driverside so it could take a two filament bulb instead of a one filament bulb?

Posted: Tue Mar 08, 2022 12:53 pm
by wesk
The simplist method is to buy another left side tail light assembly and install it on the right side. Add the service brake light wire from the left side by splicing into it. Most folks trying to hook up turn signals use this route. Going this route gives you a red service lamp lens on both sides.

You should visit my Photo Album, specifically the "Turn Signals" sub-album: http://www.willysmjeeps.com/v2/modules. ... _album.php

Posted: Tue Mar 08, 2022 6:46 pm
by Shug4
I already did that Wes. I put both tail lights the same so I could have brake and running lights on both sides. I bought a turn signal kit but my wires aren't made to take the harness on the turn signal. I was going to try to put in a two filament bulb for the brake and turn signal instead of adding another light to the back. Trying to keep it original looking.

Posted: Tue Mar 08, 2022 11:54 pm
by wesk
Adding the other light to the back was for the military turn signal kits that left the stock right tail lamp in place. If you have, as you said, installed a stock left tail light assembly in both sides you have the correct lamp sockets you need for both civvy and military turn signal setups. To offer you quality guidance on wiring you must supply us with the wiring diagram that came with your civvy turn signal switch and the switch's model number.

This is the correct way to wire in the new lt hand tail light on the right side.

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Here is one of the more popular Signal-Stat civvy turn signal kits.

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Posted: Wed Mar 09, 2022 8:00 am
by Shug4
I have the other turn signal kit. Do you have any pictures of the extra light installed on any m38a1s?

Posted: Wed Mar 09, 2022 12:39 pm
by wesk
"The other turn signal kit" doesn't help me help you. Post the kit model/make you have and if it came with one, the wiring diagram for your switch. If you already reviewed my photo albums then you have already seen the extra lamp installed on an M38A1. Hint in the one of the military turn signal kit instructions sub-album!

M38A1 Turn Signal and Brake Light Wiring

Posted: Wed Jun 19, 2024 10:51 am
by CapnDan
I have read and re-read numerous postings here on turn signals and brake lights. I am installing a Truck-Lite 900 Signal-Stat Turn Signal Switch - 7 Wire Harness (https://www.finditparts.com/products/16 ... cklite-900) on my 54 M38A1. I have a M38A1 Vintage Wiring harness installed on my Jeep. I have three bulb light fixtures installed on both left and right rear. I have the full red lenses for rear and the amber lenses for front on order.

Wiring diagram from Truck-Lite site: https://www.truck-lite.com/amfile/file/ ... uct/25669/

My question is on wiring the signal stat switch. Do I splice into the existing marker light wires and stop light wires or do I run new wires to the lights? I want to avoid some of the problems I see in the trouble shooting section of wiring diagram like have both the rear brake lights come on when using the the left or right turn signals, which seems would be the case if I connect the left rear stop to the right rear stop to have stop lights on both.

Posted: Wed Jun 19, 2024 12:40 pm
by wesk
First step to get an aswer is an accurate description of what you have. If you read the 900 SERIES Operating instructions you must know that they cover the entire 900 Series and vary according to which of the series you actually have and are installing. IE 900, 901, 902, 903, 905 and 910???

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Next we need to know exactly how you added the 2nd left light assembly on the right. IE How did you wire it into your harness. A drawing is a much better explanation than a disortation.

Armed with these answers we can help by linking the correct 900 series wiring diagram to your existing harness wiring diagram making it a quite simple transition.

Posted: Wed Jun 19, 2024 1:53 pm
by CapnDan
It is a Signal Stat 900. I have already pulled the tail lights out to clean up the connections and grounds, so the the right rear light can be connected however I need to so that it functions as a marker light, stop light, and right turn light. The right rear light was not original to the vehicle, I had installed it when I put in the new harness back in 2009, it was connected to wire numbers 23 and 24 on the new harness. The light pigtail had one wire labeled 21 and one labeled 460-461 common to two of the sockets. I intend to split the 460-461 common to two wires, one upper right for stop and one bottom center for b/o marker light. The upper left wire is tagged 21 for marker or service light.

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Posted: Wed Jun 19, 2024 11:12 pm
by wesk
Still need to see your wiring diagram that came with your new harness. It should also have your entries on it for any mods you made to the harness up to this point.

Once we post your harness' current diagram here alongside the Signal Stat 900 we can offer up reasonable suggestions.

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Posted: Thu Jun 20, 2024 5:50 am
by RonD2
Where did that diagram directly above come from?

Talk about confusing........since when are left and right front and rear anything shown as diagonal from each other?
Physically never.
That's one goofy diagram.

Posted: Thu Jun 20, 2024 6:07 am
by RonD2
Danny,
You have 3 light bulbs in each rear light housing correct?

One tail light bulb
One brake light bulb
One turn signal bulb

Q: which of those bulbs are single filament bulbs with one contact button in the center of the socket and which are something different?

If they're all singles you might want to consider exchanging your SigStat 900 for a 902.
Using a 902 allows each circuit (tail-lights, brake lights, and turn-signal lights) to be separate and independent of each other. Simple.

Posted: Thu Jun 20, 2024 10:33 am
by wesk
Ron, My apologies for insulting your intelligence with my typo. I'll try not to light your fuse again.

Capt Dan, No need to buy new light assemblies. Just rewire as indicated. I can offer better guidance if you will post the wiring diagram that came with your new aftermarket harness. be sure to anotate any changes you made during your install.

Posted: Thu Jun 20, 2024 10:35 am
by CapnDan
Wes:
The Vintage Wiring harness from Vintage wiring in Maine is built same as original harness, wiring diagram from Vintage wiring is the same as wiring diagram from TM9-8014 Chapter 3 page 213 (though that page in my digital copy is not numbered). I could scan and attach my paper copy of Vintage wiring diagram but it is not of very good quality.

I made no changes when I installed it other than the 3 bulb right rear tail light as noted above.

Ron:
Yes, three bulbs. These are the double element 24 volt bulbs with a single contact so both elements illuminate when connected to a single 24 volt wire and ground. Two are the smaller globe W1251, the larger globe is either a H1691 or 1683 (can't read number on one installed, but that is what I have in my spares). I bought the SigStat 900 because it was marked down on FindItParts website to $68 vs $110 for the 902! The 902 only has four wires, seems to be for flasher function only. The link for the Signal Stat wiring diagram is in my first post above.

I was wanting to add turn signals/flashers and the right stop light without cutting into my Vintage wiring harness. So, I am asking how best to do that, plug into existing harness with connectors or run new dedicated turn signal wires and stop light wires.

Posted: Thu Jun 20, 2024 10:39 am
by CapnDan
Note: My M38A1 does not have the three circuit breakers.