Brake Lights

This is the place to get help with technical matters concerning your M151 jeep

Moderators: rickf, raymond, Mr. Recovery

Post Reply
User avatar
Flyboy740
Staff Sergeant
Staff Sergeant
Posts: 165
Joined: December 8th, 2007, 9:43 am
Location: Richmond KY

Brake Lights

Unread post by Flyboy740 » April 5th, 2008, 10:12 pm

Here's my problem. I don't know if the brake lights have worked since I've owned the straight M151.

I put a new rear wiring harness last year. The old wires were broken, cracked and spliced in many places. I noticed that the brake lights didn't work. I replaced the braake light switch yesterday, still no lights.

I do know that the bulbs are good, I plugged the brake lights into the running light wire and they came on.

Anyone have any ideas or suggestions?
Glynn

If you don't stand behind our troops, please feel free to stand in front of them

MVPA #29026
USMCR 1976-1979
KY ARNG 1979-1996 (retired)
KSP (retired)
PGR member

1960 Ford M151
1966 Stevens M416

poppop
Private First Class
Private First Class
Posts: 11
Joined: December 9th, 2007, 7:38 pm
Location: Brooklet Ga.

Re: Brake Lights

Unread post by poppop » April 6th, 2008, 6:04 pm

It sounds like only two things are left. Are you sure you have power going into the brake light switch?? If so then are you getting a ground at the light?? Could be a third thing. I am working on a 66 Chevy pick-up with one brake light that will not work. The brake lights feed through the turn signals so that it will blink if you apply the brakes. I have isolated my problem to the signal switch in the steering column. One light is not feeding through. The Mutt probably works in the same manner.
Lloyd Strickland

User avatar
rickf
General
General
Posts: 19742
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: Brake Lights

Unread post by rickf » April 6th, 2008, 7:09 pm

This may sound dumb but is the light switch in the right position? If yes the you have to check to see if you have power to one side of the switch, If yes then trace from there back with the brakes on. If not then you could have a bad light switch, you will have to check for power out of the switch to the brake switch.
Rick
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

poppop
Private First Class
Private First Class
Posts: 11
Joined: December 9th, 2007, 7:38 pm
Location: Brooklet Ga.

Re: Brake Lights

Unread post by poppop » April 6th, 2008, 9:07 pm

I forgot about that. :oops: On a military vehicle the three lever switch has to be it the correct position for them to work. You needed to be able to turn them off so if you did not want to be seen they would not come on if you applied the brakes.
Lloyd Strickland

User avatar
Flyboy740
Staff Sergeant
Staff Sergeant
Posts: 165
Joined: December 8th, 2007, 9:43 am
Location: Richmond KY

Re: Brake Lights

Unread post by Flyboy740 » April 9th, 2008, 6:44 pm

I'll get the volt meter out and look and see about if there is current.

Bad thing is that the wires under the dash are very briddle and have been spliced in many places.
Glynn

If you don't stand behind our troops, please feel free to stand in front of them

MVPA #29026
USMCR 1976-1979
KY ARNG 1979-1996 (retired)
KSP (retired)
PGR member

1960 Ford M151
1966 Stevens M416

User avatar
rickf
General
General
Posts: 19742
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: Brake Lights

Unread post by rickf » April 9th, 2008, 8:22 pm

Flyboy740 wrote:I'll get the volt meter out and look and see about if there is current.

Bad thing is that the wires under the dash are very briddle and have been spliced in many places.
I think you just told us the problem, I would bet one of those splices is bad and inducing resistance or could be open.
Rick
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

halftracknut
Brigadier General
Brigadier General
Posts: 2065
Joined: December 11th, 2007, 2:28 pm

Re: Brake Lights

Unread post by halftracknut » April 13th, 2008, 10:19 pm

I think there are 3 breakers on a 151 under the dash??????? could be???????
slowest mutt east of the missippi..

User avatar
Flyboy740
Staff Sergeant
Staff Sergeant
Posts: 165
Joined: December 8th, 2007, 9:43 am
Location: Richmond KY

Re: Brake Lights

Unread post by Flyboy740 » April 15th, 2008, 9:31 pm

Breakers????? Could be..... Any ideas how to check one of them? I recall seeing them when I had the dash instruments out last year.
Glynn

If you don't stand behind our troops, please feel free to stand in front of them

MVPA #29026
USMCR 1976-1979
KY ARNG 1979-1996 (retired)
KSP (retired)
PGR member

1960 Ford M151
1966 Stevens M416

halftracknut
Brigadier General
Brigadier General
Posts: 2065
Joined: December 11th, 2007, 2:28 pm

Re: Brake Lights

Unread post by halftracknut » April 15th, 2008, 10:13 pm

they are bolted to inside of dash on passenger side of speedo cluster...just check for open , if current not on both sides breaker is bad....
slowest mutt east of the missippi..

Miltrans
Private First Class
Private First Class
Posts: 22
Joined: January 17th, 2008, 6:21 am
Location: Denmark

Re: Brake Lights

Unread post by Miltrans » April 16th, 2008, 9:32 am

I have just had problems with brakelights on my M35. It uses same type of brakelight switch as the Mutt. I salvaged a switch from an old Mutt and used on the M35. ..... after I had spent ages looking for the fault.
First thing I would check is therefore the switch.
"Simple job", just unplug it and short the plug with a short length of electrical cord. That is the easy part, the difficult part is getting your arm up to the switch located on the brake master cylinder.

Just to be sure that the leads have not been switched, check that it is not the black out brake lights that come on when the light switch is in the "brake light" position.
I have encountered 2 types of fault in the brakelight switch, one where the lights would not go on and another where the lights would not go out again.
Both faults had the same reason. The actual contact surfaces in the switch were burnt because of overcurrent in the brake light cirquit, 1caused by short cirquit and 2nd caused by adding too many extra brake lights ( the truck had been in civi hands and had fitted 4 rear lights, on each side! thus 4 X the amperage)
If your Mutt is equipped with the indicator lights conected to the rear brakelights, then there could be a fault here also. >Flasher relay or indicator switch.
If your Mutt has either a faulty wireing loom or had 6 Gigga Watt rear ligts at some time you may have the same problem as I have had.

Normally the brakelight switch can not be taken appart for repairs, but just to satisfy my curiousity, I savaged one of the ones I had problems with so you can see what is inside. Sorry for the poor quality of the photo.

Chris
You do not have the required permissions to view the files attached to this post.

User avatar
Flyboy740
Staff Sergeant
Staff Sergeant
Posts: 165
Joined: December 8th, 2007, 9:43 am
Location: Richmond KY

Re: Brake Lights

Unread post by Flyboy740 » April 16th, 2008, 8:12 pm

Chris,

Thanks for the post and photos of the switch. Looks like mine except I didn't take it apart. I also didn't throw it away since it might still be good. I am going to print this out and save for future reference. If I get time I'll attack this, this weekend.

Thanks,

Glynn
Glynn

If you don't stand behind our troops, please feel free to stand in front of them

MVPA #29026
USMCR 1976-1979
KY ARNG 1979-1996 (retired)
KSP (retired)
PGR member

1960 Ford M151
1966 Stevens M416

Post Reply