Bed Lighting Theorey- Good/Bad?

[mrjulian416]

I'm not enough of an automotive electronics experts to know if this would cause unintended problems...

 

To add a switch in the bed to turn on just an in-bed light, what if:

 

1. You teed into the 12v+ off the 7-pin trailer connector (always hot),
2. and ran that 12v+ feed to a toggle switch mounted somewhere handy in the bed (like near the old man handle on my GMC),
3. then ran the output of the switch into a tee connector with the existing positive feed going to the existing bed light (there by the old man handle).

 

So you flip the toggle switch and basically bypass the dash switch/control and at least put power to the light you've teed into.  No LED strip lights to hang, no holes to cut, but....

 

Does backfeeding the original line to the dash switch cause problems upstream with the dash electronics/etc?  In the good old analog/incandescent world I can't see that this would be a problem.  In the LED, solid-state, op-amp, circuit card, BCM/ECM world I'm not so sure.

 

Thoughts?  And I'm not sure I'm signing up to "try it and report back"... heh.

[Limelight]

9 hours ago, mrjulian416 said:

I'm not enough of an automotive electronics experts to know if this would cause unintended problems...

 

To add a switch in the bed to turn on just an in-bed light, what if:

 

1. You teed into the 12v+ off the 7-pin trailer connector (always hot),
2. and ran that 12v+ feed to a toggle switch mounted somewhere handy in the bed (like near the old man handle on my GMC),
3. then ran the output of the switch into a tee connector with the existing positive feed going to the existing bed light (there by the old man handle).

 

So you flip the toggle switch and basically bypass the dash switch/control and at least put power to the light you've teed into.  No LED strip lights to hang, no holes to cut, but....

 

Does backfeeding the original line to the dash switch cause problems upstream with the dash electronics/etc?  In the good old analog/incandescent world I can't see that this would be a problem.  In the LED, solid-state, op-amp, circuit card, BCM/ECM world I'm not so sure.

 

Thoughts?  And I'm not sure I'm signing up to "try it and report back"... heh.

I wired mine in with a switch and 12v+ in the bed,  No issues upstream like you describe.  I also wired in a programmable timer I found on Amazon so If I accidentally leave the bed lights on, it'll shut em off after 5 minutes.  If you flick the switch off then on again it resets the timer.  Works great.  Here's a link to the timer- amazing flexible.  You program it on your bench and then install...

10 Amp Mini Timer Time Delay Relay .2 Sec to 400 days 6V 12V 18V. Power On Off Delay, Cycling and Trigger - - Amazon.com

 

Edited May 19, 2021 by Limelight

[Rozz522]

I would say for this installation, a cheap inline blocking diode would be cheap insurance. Wire it to the console switch side of the T you are installing in order to allow power flow from the console switch but prevent back-feed. I assume that the different LEDs in the bed are all in parallel so the additional 1.7V drop across the blocking diode shouldn’t be an issue. 

[mrjulian416]

10 hours ago, Limelight said:

I wired mine in with a switch and 12v+ in the bed,  No issues upstream like you describe.  I also wired in a programmable timer I found on Amazon so If I accidentally leave the bed lights on, it'll shut em off after 5 minutes.  If you flick the switch off then on again it resets the timer.  Works great.  Here's a link to the timer- amazing flexible.  You program it on your bench and then install...

10 Amp Mini Timer Time Delay Relay .2 Sec to 400 days 6V 12V 18V. Power On Off Delay, Cycling and Trigger - - Amazon.com

 

That is a cool idea.  Did you find a good weatherproof switch as well?

 

Rozz, I like the idea of a diode as well... just in case.

[Limelight]

On 5/19/2021 at 8:59 AM, mrjulian416 said:

That is a cool idea.  Did you find a good weatherproof switch as well?

 

Rozz, I like the idea of a diode as well... just in case.

I just used a switch I had in the electric project box...

I keep the tonneau cover on so it's fairly protected.  I always coat my connections with dielectric grease and marine heatshrink so everything else is solid.