JHZR2
Staff member
My 4wd Ram hasn’t had a functioning brake light since Ive owned it. It has a brake controller for trailering, and the brakes all work perfect. No issues with vac assist, fluid, parking brake, etc. Just no dummy light, either at the light check at startup, nor when the parking brake is applied, etc.
I think based upon this diagram, the brake light bulb should always have a hot side. Assuming the fuses are in place and functional (they are). So I should be able to probe with my meter and find 12v when the truck is on, on one side of the bulb socket. Does anyone disagree?
The other odd thing is the vacuum sensor. The brakes are vac assisted, and the abs and brake warning light will illuminate when vac is too low. It’s strange to me that it isnt just a switch, there’s voltage to it. I’m assuming that it’s some sort of active switch that connects to ground when it senses vac is too low. Anyone else understand how these sorts of vacuum sense switches work? I don’t think there’s a need for a biased signal, there’s no AT that is basing shifting on vacuum (as in my diesel Mercedes), and it only feeds dummy lights.
Any thoughts?
I think based upon this diagram, the brake light bulb should always have a hot side. Assuming the fuses are in place and functional (they are). So I should be able to probe with my meter and find 12v when the truck is on, on one side of the bulb socket. Does anyone disagree?
The other odd thing is the vacuum sensor. The brakes are vac assisted, and the abs and brake warning light will illuminate when vac is too low. It’s strange to me that it isnt just a switch, there’s voltage to it. I’m assuming that it’s some sort of active switch that connects to ground when it senses vac is too low. Anyone else understand how these sorts of vacuum sense switches work? I don’t think there’s a need for a biased signal, there’s no AT that is basing shifting on vacuum (as in my diesel Mercedes), and it only feeds dummy lights.
Any thoughts?