Relay to turn on brake and turn signals with ignition on?

[FlameRed]

Hello,

Another newbie 92 M998 question.

I am trying to rig up a relay so that when I turn the ignition to run, I wanted to turn on the brake lights and turn signals without touching the light switch so I don't forget to turn them on.

For the turn signals, no problem, I found lead that Lead J off the light switch with circuit 467 was to flasher switch so the relay does now enable the turn signals when I turn the ignition to run.

But the brake lights are harder. I tried applying +24V to lead A circuit 75 which the diagram show as Stop Lamp Switch. No joy, the brake lights will not come on when the brakes are applied.

I also tried Lead K Circuit 75 which is also marked as Stop Lamp Switch - no joy.

I also tried Lead C circuit 22 labeled Stop Lights, but then the brake lights seem to come on when the brake pedal is not pressed.

Does anyone have any experience figuring out which leads off the light switch need to be activated to get the brake lights to work?

Thank you!

 

[Mogman]

Yes making 75A hot should give you brake lights, LET ME DOUBLE CHECK THAT

 

[knighthawkgamer]

Black Dog Customs makes a kit that accomplishes this already. The kit is $89 and pretty simple install.

Automatic Light Switch Kit - Black Dog Customs

Automatic Light Switch Kit Never forget to turn your lights on/off again! When you flip your switch to the run position, your lights (headlights, taillights, turn signals), come on; when you flip your switch to the off position, your lights turn off! Installation typically takes 15-20 minutes...

blackdogcustoms.com

 

[Mogman]

Looks like for the brake lights 75A is hot, I made this hot all the time so the brake lights would work no matter what position the run switch was in, you will also have to bypass the switch with wires 75B (K on the light switch) to 22A (C on the light switch) to get the 24V from the brake light switch to the turn signal switch. I removed all of these from the light switch so I would not back feed any other circuits and of course fused 75A

 

[Mogman]

467 from the light switch feeds the turn signals, I fused this to switched power so the turn signals would not be powered all the time, I think that also powers some other stuff on the later trucks so making it hot all the time may not be a good idea. That should also power the horn

 

[Mogman]

Of course test all of this carefully before making it permanent

 

[Mogman]

You could also isolate pin G (467) at the turn signal switch and fuse it hot all the time, this would make the turn signals "work" all the time but also it would allow the emergency flashers to be used no matter what position the run switch is in which may be a safety consideration.
which is one of the problems I see with the Back Dog kit, I want to be able to power my headlights with the run switch off if I want to.
It looks like all the BD kit does is switch all the power to the light switch (15A pin F) so you would have to run with the light switch in service drive or stoplight position, but none of the lights would work with the run switch off.

 

[FlameRed]

Looks like for the brake lights 75A is hot, I made this hot all the time so the brake lights would work no matter what position the run switch was in, you will also have to bypass the switch with wires 75B (K on the light switch) to 22A (C on the light switch) to get the 24V from the brake light switch to the turn signal switch. I removed all of these from the light switch so I would bot back feed any other circuits and of course fused 75A

Perfect! I was missing the 75B to 22A and now it works great! Thank you!

 

[Action]

Cant you just leave the light switch in the first position and shut the dash lights off?

 

[Guruman]

I'm looking to do something similar to my lmtv. My plan was to disconnect the always on power feeding the light switch ("F" on the cannon connector in my case), and replace it with a switched power source. I could then leave my light switch "on" all the time, and the lights would power on and off with the truck. I would also retain the ability to use any setting on the switch once the power was on. Retaining my ability to turn off the lights or use the BO system if I wanted.

I got the idea from here and just modified what he did to make it fit my needs: https://builtmfg.com/2017/11/02/light-rewire/

What he did does not really directly relate to what I'm doing, but there is some good info there.

Edit: Here's a video of the linked procedure.

 

[Mogman]

I'm looking to do something similar to my lmtv. My plan was to disconnect the always on power feeding the light switch ("F" on the cannon connector in my case), and replace it with a switched power source. I could then leave my light switch "on" all the time, and the lights would power on and off with the truck. I would also retain the ability to use any setting on the switch once the power was on. Retaining my ability to turn off the lights or use the BO system if I wanted.

I got the idea from here and just modified what he did to make it fit my needs: https://builtmfg.com/2017/11/02/light-rewire/

What he did does not really directly relate to what I'm doing, but there is some good info there.

Edit: Here's a video of the linked procedure.

[/QUOTE


Yes, just like I said in post #7 it is the easiest but no lights can be turned on with the truck turned off, somewhat of a safety issue and at times inconvenient.

Yes, just like I said in post #7 it is the easiest but no lights can be turned on with the truck turned off, somewhat of a safety issue and at times inconvenient.
Edit, lets say you are driving down the road at night and all of a sudden you have an issue with the engine, you reach over and turn off the run switch and you now have zero lights.

 

[dmetalmiki]

I am puzzled..The lights should already function with the engine off?
It is a diesel truck so if you switched off the engine to check things the ignition COULD be left on..BUT SAFETY decrees that the 4 ways work at all times.
You break down, (On any vehicle created!) and you SHOULD be able to warn other road users (LAW vehicle type and construction). of this fact. With ignition/master switches on or off.
Army trucks have switching for Brake lights, Drive. Park. Convoy. Blackout. Blackout drive,
And one of those functions should give you the options you are looking for.
Well, they certainly do on all my ex military trucks.
Even my WW11 jeeps.
And not to be too 'pedantic..But You drive a car?..I mind you do not have a relay to operate either the flashers brake lights When the ignition is turned on?...In case..you..Forget??
Jus' my 1/2 penneth...soz if im incorrect.

 

[Guruman]

The hazards in my lmtv are activated by a toggle switch in the panel, which I'm assuming gets power all the time. Maybe I'm wrong, but I don't think changing the power feed to the switch would affect that.

@dmetalmiki For me, my issue is not with forgetting and leaving the lights on. It's forgetting and taking off leaving them OFF. My civilian rides do not require me to manually enable the stop and turn lights every time. For me that is much more of a hazard than needing to leave it switched on to use the hazards (if that were even required).

I'd much rather they come on by default than remain off by default. I can survive the humiliation of forgetting and looking like a dummy, even a ticket for it would not be the end of the world. But man, would I be sad if someone rear-ended my 18k pound truck and got hurt or killed because I forgot to operate the stupid levers. Fixing the all-lights off by default is high on my list.

 

[Mogman]

The hazards in my lmtv are activated by a toggle switch in the panel, which I'm assuming gets power all the time. Maybe I'm wrong, but I don't think changing the power feed to the switch would affect that.

@dmetalmiki For me, my issue is not with forgetting and leaving the lights on. It's forgetting and taking off leaving them OFF. My civilian rides do not require me to manually enable the stop and turn lights every time. For me that is much more of a hazard than needing to leave it switched on to use the hazards (if that were even required).

I'd much rather they come on by default than remain off by default. I can survive the humiliation of forgetting and looking like a dummy, even a ticket for it would not be the end of the world. But man, would I be sad if someone rear-ended my 18k pound truck and got hurt or killed because I forgot to operate the stupid levers. Fixing the all-lights off by default is high on my list.

Like I said it is one of the easiest to do, but there are other ways also

 

[Action]

Hang a tag on the start switch with “turn lights on” written on both sides.

 

[Andyrv6av8r]

I have a heavy duty relay on the positve battery lead contrlled by a keyed switch on the dash. I leave my light switch in the ON position always. Insert the key and turn on; lights are on. Then start the engine with the normal start button. I have used this setup in 5 trucks with no issues.

 

[GopherHill]

After you have used a military vehicle for a daily driver, that switch operation becomes muscle memory.

 

[Coug]

I just use a battery disconnect keyed switch near the doghouse. You can leave the light switch in any position you want and nothing will drain with the keyed switch turned to off.

 

[Maxjeep1]

I have a start and stop routine that I always try to do in the same order. I very rarely forget to turn them on. I need to be able to drive without lights when I’m out poaching. Lol

 

[Milcommoguy]

I have a start and stop routine that I always try to do in the same order. I very rarely forget to turn them on. I need to be able to drive without lights when I’m out poaching. Lol

Poaching ?? on Las Vegas Blvd... Don't need lights.

Blinded by the lights, CAMO