Tail light wiring issues

[Dbleeger]

Hi everybody! New to the forum, but have worked on my GFs 2003 Astro for a few years and just purchased for myself a 1991 Astro GT Tiger. It's a project van that I'm hoping to get into shape for a road trip back West in 8 months.

The previous owner tore out the original taillights and I purchased some Bargman Trailer Lights - 47-84-104 to replace them. The wiring harness coming from the cab looks like the standard trailer light harness (yellow, green, brown, white). As far as I can tell: yellow= left turn & brake, green= right turn & brake, brown= running lights, white= reverse lights- I found it odd that white wasn't ground and will look more into it

The problem I'm running into is that when I wire everything up it all works except for when I signal a turn and brake. With a turn signal on the amber light blinks and so does the red brake light on the same side. I don't think that's normal, but not terrible. The real problem though is when the blinker is on and I hit the brakes. The amber and red light both turn solid. I don't like the idea of losing my turn signals when I brake

Has anybody experienced similar issues or know where I am going wrong?

[Rod's Trucks]

I am quite sure you have a missing ground to the light housing. What you seem to be experiencing is a very common situation on many motor homes that have wood or fiberglass bodies. There has to be a frame ground provided, in some fashion, for the dual filament lamps to work properly.
Try using something simple like a clip lead from the metal of the lamp housing, to a known frame ground.
If the housing has no identifiable ground lead, then you will need to trace the wires in the fixture to see which one is the common lead. The common lead will go to the lamp base ( or multiple bases, depending on the fixture) . The other wires will each go to the different filaments. I have seen some lamp fixtures where one of the mounting screw bosses has a metal grommet built in. That grommet most be connected to a wire that goes to the frame ground.
Rod J

[markmitch]

I have the wirings schematics book for an 89 I can take a look in the book and see what is what and let you know. Mark

[CopperFiremist]

Ground

[Dbleeger]

I have the taillights grounded to the aluminum frame of the van body, but I will clean the contacts and double-check the connections today. I will also try running a ground directly to the frame versus the aluminum van body. I will let you all know! Thanks

[AstroOafAdventurer]

Ground directly to the frame. Forget the aluminum.

[AstroWill]

Congrats on the Tiger and welcome to the site!

You stated that the amber lights were lit up, they should not be lit up at all, our vans are not set up for that. It would require custom wiring to be able to use the amber turn signals so easiest is to not use them at all.

Make sure that the running lights and the brake/turn wire from the van is only connected to the proper RED set of LEDs.
1wire for running lights(wired to the low side of the red LEDs on both sides), 1 wire for each brake/turn light(wired to the high side of the red LEDs on each side), 1 wire for reverse(wired to the white LEDs), 1 wire for ground.

So for each replacement light/housing you will be using the 2 power wires from the outside RED lights, and 1 power wire from the WHITE reverse light, and the ground is shared for all of them.


If you wanted to set them up to use the amber for the rear turn signal, it will require 3 new wires from the front of the van. But I'm not going to get into that unless that is your plan.

[Dbleeger]

AstroWill thank you for the info! This is a huge help.

After playing around with the ground yesterday it makes sense that the Tiger isn't wired for ambers. I have one of the original taillights and it doesn't have an amber light on it either. That should have got me thinking along that path sooner.

[AstroWill]

You are most welcome.

Yep, none of our vans are wired for amber rear turn signals, except for a couple of export vans I have seen. They should be, but that is another story.

[AstroWill]

Now that it's fixed, want to share a picture of them installed and in action?

[Dbleeger]

I couldn't find tail lights that are the exact dimensions of the originals, but the ones I went with are the correct width and 3 inches shy in length. I fabricated an aluminum collar to fill up the space around the sides and got it all wired and mounted today. Finally street legal!

Now on to the next project!

[Rod's Trucks]

It is good that you found and 'fixed' the problem.
What did you find to be the actual problem, for future reference..
Rod J
Issaquah, WA

[Dbleeger]

I had originally bought taillights with an amber lens, but the van isn't wired for having an amber. So not as much of a fix but more of a just buying the correct parts!

[AstroWill]

I couldn't find tail lights that are the exact dimensions of the originals, but the ones I went with are the correct width and 3 inches shy in length. I fabricated an aluminum collar to fill up the space around the sides and got it all wired and mounted today. Finally street legal!

Now on to the next project!

Could have still used the others and just not wired it up for the amber lights, but I think the new ones look nice!

One of my Tigers was done the same way, because the same sized housings could not be found. Congrats on being street legal!

[sixsix]

... After playing around with the ground yesterday it makes sense that the Tiger isn't wired for ambers.

Yep, none of our vans are wired for amber rear turn signals,

I had originally bought taillights with an amber lens, but the van isn't wired for having an amber. So not as much of a fix but more of a just buying the correct parts!

Almost makes it sound like Amber lights used for any purpose are "Wired Special" - aren't we just talking Lenses?
Or do these "Amber Lights" require some 24 volt foreign spec? Probably illegal in the state(s).