M35A2 Tail Light Question

[Big Strapper]

I recently noticed my right tail light was dimmer than the left. When I took the lens assemblies off both, I found the two are not the same, & the right tail light bulb was melting the right lens. This is because the right lens frame is thinner than the left, placing the lens too close to the bulb. The left tail light also has a cube with LED looking lights in the bottom of it which the right does not have.

My question is, should both sides be the same, or are they supposed to be different? Has someone put an incorrect tail light on? I know the bulb should not melt the lens, so something is screwey.

Any feedback is appreciated. I apologize in advance for not understanding the black-out lighting system functions.

 

[poppop]

Sounds like one side was updated with the newer led lights. The bulbs are suppossed to be rather small. I have one on my desk and the glass part is only about one half inch tall, Has someone put a larger bulb in there??

 

[Big Strapper]

Each tail light actually has two glass bulbs, one above the other. The upper bulb is a medium-sized bulb that lights when the tail lights are turned on. The lower bulb is larger & looks similar to a 12V 1157 automotive bulb & is for the brake lights. Below the left larger bulb is the plastic cube with the small LED lights. I believe this is for the black-out system but I don't know for sure. The right side does not have this device.

 

[jimm1009]

THIS DEPENDS ON WHAT VERSION OF TAIL LIGHT THAT YOU HAVE (AND FWD. PARKING LIGHT)
The 2nd and 3rd generation have a total of four light bulbs installed. (4th generation is a complete LED assy. and is not included here).

The upper bulb #623 is the tail light. The 2nd bulb down #1683 and in the same cavity is the brake & turn bulb. The 3rd bulb down #1251 in a cavity by itself is a smaller bulb and is the Blackout brake light. The 4th bulb down #1251 and again in it's own cavity, is the blackout tail light. Reference TM9-2320-209-20P figures 77 & 78.
It appears that the early trucks did not have a brake light in the right-side tail light although it appears that they were wired for one. Ref. same TM 9-2320-209-20P figures 71 & 72. The bulbs are 1683 & 1251.
NOTE: If you want, you can use the 623 bulb in the lower two positions in the later tail lights and it give you a slighly brighter blackout set of lights but this is up to you. If I had the 1st generation tail lights I would install the 1683 bulb in both brake light positions as it will be a lot safer that way but would not be "Historically Correct".
I hope this helps.
jimm1009

 

[drivebymashing]

I installed the 1683 in both upper positions and the top position needs a smaller bulb. its really close to lense if not touches the lens. It melted lens and busted the bulb im guessing from heat.