Lights-, directional- and stoplight switch

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

Moderators: rickf, raymond, Mr. Recovery

Post Reply
dr. trinkmann
Sergeant
Sergeant
Posts: 68
Joined: October 12th, 2016, 5:58 pm
Location: Germany, Bavaria, Ufr.

Lights-, directional- and stoplight switch

Unread post by dr. trinkmann » June 4th, 2018, 2:58 am

Hello everybody,
today I have a question about the lights mainswitch, the directional switch and the stoplight's switch (M151A2).
Are any or all of theese well known to wear and become defective?

Have a nice day
dr. trinkmann

User avatar
svramselaar
Major
Major
Posts: 1107
Joined: December 30th, 2007, 6:48 am
Location: holland

Re: Lights-, directional- and stoplight switch

Unread post by svramselaar » June 4th, 2018, 6:07 am

hi

all switches can go bad by wear and tear
at the light and directional switch are automatic fuses inside

if the brake switch is not correect adjusted is go faster bad (it is also at a M113 )


george

dr. trinkmann
Sergeant
Sergeant
Posts: 68
Joined: October 12th, 2016, 5:58 pm
Location: Germany, Bavaria, Ufr.

Re: Lights-, directional- and stoplight switch

Unread post by dr. trinkmann » June 4th, 2018, 6:50 am

Stoplight switch worked fine but this wekend I had no stoplights at all.
Had to adjust the nuts of the rod between pedal andstoplight switch all the way out (maximum length) to get it working again.
I don't know why this adjustment was way out...

dr. trinkmann
Sergeant
Sergeant
Posts: 68
Joined: October 12th, 2016, 5:58 pm
Location: Germany, Bavaria, Ufr.

Re: Lights-, directional- and stoplight switch

Unread post by dr. trinkmann » June 4th, 2018, 10:22 am

additional question: can the main light switch and the directional switch be opened for maintenance?

thx
dr. trinkmann

User avatar
m3a1
Lt. General
Lt. General
Posts: 4029
Joined: August 7th, 2014, 6:36 pm

Re: Lights-, directional- and stoplight switch

Unread post by m3a1 » June 4th, 2018, 11:19 am

Mechanical adjustment issues at the switch's push-rod may result from a change in the brake pedal free travel. There is a lock nut and an eccentric bolt up at the point where the pedal swings. Check that first before you pursue the electrical gremlins.

Details on adjusting brake pedal free travel can be found in the TM 9-2320-218-20, Page 2-202, paragraph 2-171.

As an aside - Having the brake switch slightly out of adjustment may also drain your battery (or batteries.) I found mine was set improperly and was sending only the slightest amount of current to my stop lights which I found upon close inspection, were just barely on and yes, I was one of those guys who routinely left my service light switch in the ON position for fear of forgetting it when driving. So, if you have a mysterious drain on your batteries, start by ensuring that you keep your service light switch OFF when your truck is not in use.

Cheers,
TJ

User avatar
rickf
General
General
Posts: 19740
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: Lights-, directional- and stoplight switch

Unread post by rickf » June 4th, 2018, 2:12 pm

I have not turned my service light switch off in five years. Never had an issue with battery drain other than normal drain from sitting.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

dr. trinkmann
Sergeant
Sergeant
Posts: 68
Joined: October 12th, 2016, 5:58 pm
Location: Germany, Bavaria, Ufr.

Re: Lights-, directional- and stoplight switch

Unread post by dr. trinkmann » June 4th, 2018, 6:08 pm

Ok guys, found the bug in the System:
Furtunatelly it was the easiest of all possible fails: the housing of the left taillight had completely lost electrical ground what caused strange behaviour with all the bulbs inside while grabbing ground from elsewhere...

Nevertheless the the stopnut on the pushrod now had to be set to max. length to get stoplight with slight breaking.
Didn't change the pedal free travel, but only had a bad wheel cylinder on front axle last year.
Changed both and, off corse, had to drain service break.
Nothing else done with the breaks sinc then.
Will check that chapter with pedal travel...

I asume doing all that electrical switching without any relais will burn the contacts inside the switches by time...

Btw: my Version of a (german) amber flashing taillight: https://picload.org/view/doigaaoi/ruecklicht.jpg.html
Better did that photo without flashlight :roll:

thx
dr. trinkmann

User avatar
m3a1
Lt. General
Lt. General
Posts: 4029
Joined: August 7th, 2014, 6:36 pm

Re: Lights-, directional- and stoplight switch

Unread post by m3a1 » June 4th, 2018, 7:30 pm

Rick, my pedal was not returning all the way back to it's normal position, thus the brake lights were on and only just by the thinnest margin. In leaving the service lights in the on position, it allowed current to flow. Remember when my batteries were suddenly going to pot? THAT is what the problem was.

kmam
Sergeant Major
Sergeant Major
Posts: 524
Joined: June 6th, 2015, 7:39 am
Location: Kuranda, Far North Queensland, Australia

Re: Lights-, directional- and stoplight switch

Unread post by kmam » June 4th, 2018, 8:46 pm

I think the mechanical stop light switch was a backward step for no apparent benefit. I replaced mine with a hydraulic switch and those problems go away.
Howard

Daimler Ferret Mk 1/2
AM General M151A2
Austin Champ

User avatar
rickf
General
General
Posts: 19740
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: Lights-, directional- and stoplight switch

Unread post by rickf » June 4th, 2018, 8:57 pm

kmam wrote:I think the mechanical stop light switch was a backward step for no apparent benefit. I replaced mine with a hydraulic switch and those problems go away.
Bingo!
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Fil Bonica
Brigadier General
Brigadier General
Posts: 2607
Joined: December 9th, 2007, 10:49 am
Location: ~ Heaven ~

Re: Lights-, directional- and stoplight switch

Unread post by Fil Bonica » June 5th, 2018, 10:01 am

Interesting,
Never could understand why the mechanical switch was used when hydraulics were used for so long.
Always wanted to try hydraulic in its place .

Good luck

Fil Bonica
K1ABW

kmam
Sergeant Major
Sergeant Major
Posts: 524
Joined: June 6th, 2015, 7:39 am
Location: Kuranda, Far North Queensland, Australia

Re: Lights-, directional- and stoplight switch

Unread post by kmam » June 5th, 2018, 4:49 pm

Especially when the hydraulic switches are a standard off the shelf item.
Howard

Daimler Ferret Mk 1/2
AM General M151A2
Austin Champ

Post Reply