Ok, then the wires stop at one of the other in-line connectors. No sense in chasing them down because you don’t have the correct terminals for any of those connectors, and you’d be hacking up the kit harness. Just remove the wires that are present on the PDC and BCM connectors, and insert the wires from the kit.
Ram Heavy Duty Forum
Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!
LED Cargo Bed Lights Wiring ?????
- Thread starter el_barto
- Start date
Muddy Thumper
New Member
- Joined
- Nov 22, 2020
- Messages
- 16
- Reaction score
- 12
I am interested in the under rail lighting and will follow this thread. Thanks.
What/whose lights did you use here?
Seems anything I order from Amazon ends up being garbage that doesn't last (like Recon cab lights).
I plan on installing an aftermarket strip light and an aftermarket switch since I can't fit the OEM switch with my liner. Therefore I have to make my own harness. A couple questions:
1. Is C7/P16 the hot from the lights, and C3/P17 hot from the switch?
2. Is it a simple click on/click off switch or something more complicated.
1. Is C7/P16 the hot from the lights, and C3/P17 hot from the switch?
2. Is it a simple click on/click off switch or something more complicated.
BCM C7 pin 16 it the signal from the bed light switch.
PDC C3 pin 17 is the power supply for the bed lights.
It is not a simple on off switch. The switch sends a pulse to BCM C7/P16, then the BCM enables the run relay control circuit, which activates the relay in the PDC to send power out of C3/P17 to the bed lights. The next pulse seen from the bed light switch will disable the run relay control circuit.
Do these filters look correct? Momentary on, 12V, SPST?
Non of those will work in place of the factory bed light switch, because the factory switch has a resistive membrane to send the pulse to the bcm. To use one of those, you’ll have to divorce the bed light system from the bcm, and wire it up like any othe aftermarket light with switch and relay.
Na, I'm reserved to do it correctly.
I work in the electronic components industry but I am not an engineer, so I know enough to be dangerous. Why would the pulse from the elctromechanical switch be different than what the PCB sends in the membrane switch? Is it sending different types of pulses to signal the BCM? I would figure the membrane switch was for environmental and asthetic purposes.
It must be, and I don’t know how to measure it. I tried exactly what you are trying in 2017 when the bed lights were an option, but the bed switch didn’t exist yet until the 2018’s. I enabled the circuit on the bcm, and tried using a few different switches, and got nothing out of them.
I do have a bed light switch in my parts stash that I can mess around with to see if the bcm is looking for a certain resistance with the pulse.
Brewbud
Brewmeister Meisterbrew
Interesting. Does the BCM use PWM for these signals?
I’d say most likely.
I just played a game of stump the engineer and he couldn't give an answer with confidence. They could put as much or as little as they wanted on the PCB vs in the computer. It makes more sense to have as simple of a switch as possible but it's a dangerous game to confirm that. In your experience, would Ram answer these types of questions?
If it's a total dead end I will buy the OEM switch and hack it up to fit my needs.
It's not, I could just wire them directly the battery and be done with it. But I'd like to use the computer to control them rather than worry if I shut them off or fumble for a toggle switch in the dark. The only reason it's complicated is because I want to use all my own components but tie them into the OEM computer. My liner will not allow for an OEM install and I don't think the OEM lights are very good anyway.
Per this source, they are using PWM for output. Sounds like they aren't for input?
I’m a little more than stumped on this one. Just took a factory switch apart as far as I could. I can see the raw push button and the two contacts that lead to the connector. I can’t see what’s inside under the button without destroying the housing. When I push the button, there is almost zero resistance between the two circuits. So, I’m not too sure. All I know is when I tried regular momentary switches, no go. As soon as I plugged in the factory switch, it worked. I also tested this same behavior with the tailgate release switch- regular momentary switch won’t let the BCM operate the latches.
As far as not using the factory switch, is this like a drop in bed liner? I know many have mounted the factory switch in the plastic bed liners, it just snaps right in.
Just to be clear I stumped an engineer at work, was not referring to you.
Its a bed rug so too thick to flush mount. I could probably make a shallow block out of fiberglass and transfer the cutout onto it if push came to shove.
I emailed Ram to get specs on the switch and gave details of why I was asking. It might be a foregone conclusion but I'd like to know for sure.
Some sort of capacitive membrane switch?
Possibly. I’ve had this switch just sitting in the parts stash for about a year. I don’t think I’ll be able to help myself and just end up cutting the sucker open to check it out.
Do you have any way to check it other than continuity?
Like an ESR meter?
How hard is it to pull that switch from the bed? I have an ESR meter here as well as some other test gear I might be able to figure something out. But it's 14F here and supposed to snow and no garage big enough to stay warm.
Do we know what is on the wire side? Power/LIN/GND, etc. ?
Like an ESR meter?
How hard is it to pull that switch from the bed? I have an ESR meter here as well as some other test gear I might be able to figure something out. But it's 14F here and supposed to snow and no garage big enough to stay warm.
Do we know what is on the wire side? Power/LIN/GND, etc. ?