M998 STOPLIGHT SWITCH ADJUSTMENT?

[Iambiig]

Is there an adjustment on the stop light switch? Having to push really hard in order for the brake lights to come on.

 

[Ajax MD]

Yes. There's a procedure in one of the TM's. I followed the procedure and it worked perfectly.
Let me see if I can find it...

ETA: Here- TM-9-2320-280-20-2.pdf (steelsoldiers.com) page 4-98.

 

[papakb]

One more time: The standard incandescent lights on most military vehicles draw a lot of current and this tends to arc out the contacts in the brake light switch making you press harder and harder over time to make them come on. In the HMMWV this is compounded by the fact that there is no free travel adjustment on the linkage. Just a piss poor design. By the time you readjust the switch to get the lights to come on the brakes have already come on and if you stand on them too hard your standing the vehicle on it's nose! One thing the HMMWV does have is good brakes!

Your best option is to change the brake lights to LEDs to drop the current draw. By doing this your new brake light switch should last a lifetime. It wouldn't hurt to change all your lights to LEDs. If you look around you can find 10-30 volt LEDs so you don't need to make any changes to the wiring when you install them like you would if you just had 12 volt LEDs. It never hurts to look at all the lamp sockets and wiring at the same time. This is one of the more trouble prone parts of the HMMWV.

The only one you'll have a problem with is the blackout lights because manufacturers make LEDs to be bright, not dim. Yes, you can add dropping resistors to limit current but most people wouldn't know how to do this. The other option is to partially paint the LED black to dim them which isn't a problem because they don't get hot like incandescent lights do.

 

[FlameRed]

One other comment I have to the above while changing your buld - check your grounds on each light if you have anything weird, like lights out, dim, etc. Many of mine were heavily corroded and did all kinds of weird things. I had to change ground wires, bolts on both rears. The front grounds were not bad since they were protected a bit.

 

[Iambiig]

Yes. There's a procedure in one of the TM's. I followed the procedure and it worked perfectly.
Let me see if I can find it...

ETA: Here- TM-9-2320-280-20-2.pdf (steelsoldiers.com) page 4-98.

This is great, Thank you. I had the -1 TM, but that didn't cover this

 

[Ajax MD]

The only one you'll have a problem with is the blackout lights because manufacturers make LEDs to be bright, not dim.

On that note, I discovered what appear to be milspec blackout LEDs inside my brake and signal buckets. That was a surprise and a treat.

 

[Iambiig]

One more time: The standard incandescent lights on most military vehicles draw a lot of current and this tends to arc out the contacts in the brake light switch making you press harder and harder over time to make them come on. In the HMMWV this is compounded by the fact that there is no free travel adjustment on the linkage. Just a piss poor design. By the time you readjust the switch to get the lights to come on the brakes have already come on and if you stand on them too hard your standing the vehicle on it's nose! One thing the HMMWV does have is good brakes!

Your best option is to change the brake lights to LEDs to drop the current draw. By doing this your new brake light switch should last a lifetime. It wouldn't hurt to change all your lights to LEDs. If you look around you can find 10-30 volt LEDs so you don't need to make any changes to the wiring when you install them like you would if you just had 12 volt LEDs. It never hurts to look at all the lamp sockets and wiring at the same time. This is one of the more trouble prone parts of the HMMWV.

The only one you'll have a problem with is the blackout lights because manufacturers make LEDs to be bright, not dim. Yes, you can add dropping resistors to limit current but most people wouldn't know how to do this. The other option is to partially paint the LED black to dim them which isn't a problem because they don't get hot like incandescent lights do.

Thanks again?? I did change out all the incandescents with LED's when I first got the truck. There is a definite clunk when depressing the pedal. The clunk would be the switch being engaged. It is lower than it should be (to the point of locking up the brakes in order to activate the lights). I will adjust the switch based on the TM and go from there. Thanks again