If you want to add bed lighting that is not difficult. There are endless lighting schemes out there on Amazon and auto parts retailers. Connecting the dots can be done once we are all on the same channel as to exactly in detail what you want. Just remember whatever is outside the truck interior will be exposed to the elements so you want weather proof stuff which is not a problem. So you decide the components and pretty sure anyone here can make diagram suggestions.

Ron

 

I have a cover on the bed, so any lighting would be on the inside kind of tucked under the lip of the bed. I’ve seen plenty of pictures of people doing that same concept and it seems to be just fine and barely gets a bit of water unless you’re going through a monsoon

 

I also have a timed power supply coming from the battery to inside the cab.

That's new information. What exactly is the purpose of the timed power supply?

it would be nice to possibly have it also activate some strip lights in the bed of the truck.

That's easy enough. Since the tailgate open switch will activate the ITC (Inside The Cab) indicator it can also provide a pathway to ground for strip lighting in the bed. One switch can accomplish both tasks. Just be sure to use a switched power source or you could drain your battery if the tailgate is not fully closed, leaving both the ITC indicator and bed lighting on.

 

Here's a drawing of how it'd work: If the door is open then the bed lights and the ITC will be lit when the key is on. Door closed, no bed lights and no ITC. Key off - no bed lights, no ITC.

 

Well I should have clarified that the timed aspect is via the trucks accessories fuse. Think it stays on for 5 minutes or when the voltage drops below a certain point.

 

There are so many fuses in a vehicle. Some fuses are always powered, some are powered only when the key is on. I've never heard of a timed fuse. If you're talking about dome lights that fade to off a set period of time after the door is closed - that's usually less than one minute. IF you have such a timed circuit, which I think it's more likely timed by the computer rather than a timed fuse - but I don't know everything, so - - - if you DO have such a circuit then instead of the key'd power source you can use said "timed fuse". But what if you want the bed lights to be on longer than 5 minutes? You don't have to put everything through a single circuit. You can make bed lights separate from a timed source so the bed can be lit whenever the tailgate is open regardless of the key position.

You can also add a bypass switch to turn the lights on even if the tailgate is closed. You'd bypass the tailgate switch.

Anyway, I'm still not 100% sure I know what you're after. AFAIK - a dashboard light that indicates an open tailgate. And of late, a bed light. The timer throws me off.

 

This is a response to the original request, not about lighting the truck bed.
If the requirement is for "open" meaning not closed and latched, then one option without runnung another wire is to use the backup light wire. When the gate is latched up, a capacitor gets connected between the backup light wire and body common ground. An oscillator up front sends a signal into the wire and the cap loads it down, but when the gate is unlatched the signal is not bypassed to common. So it can be detected and used to trigger an indicator. The only flaw is that it will not work , probably, when backing up. You may need to install a lowresistance choke coil between the backup light and the wire, though.

 

@MisterBill2 are you saying the backup light is always powered and only lights when the transmission is in reverse? It does make sense. If so then the TS has a ready source of power at the back of the truck. Here's a proposal for the TS: set up a lighted bed. When the tailgate is open the bed is lit. Look in the rear view mirror and you see the bed lights on you know the tailgate is open.

Moderators: This is not a hijacking of the thread. The question posed is to clarify whether the TS can use the reverse light as a source of power. Me? If I wanted to know this I'd just go test my truck.

@MisterBill2 the TS wants an indicator in the cab. Maybe the TS has a shell and can't visually see if the tailgate is open or not without walking behind the truck. The additional notion of bed lighting is a secondary question from the TS, but the main focus is on an ITC indicator (In The Cab).

 

The backup light connection is typically only powered when the vehicle is in reverse. I suggested a method of using one wire for two functions without requiring any additional power at the rear of the truck.
There may be additional wires in that area depending on the model and age of the truck. The older vehicles had usually 4 circuits: Fuel sensor, tail lights, left turn/stop, right turn/stop, and possibly a ground/negative wire. Newer vehicles will have a few more, not needed with the scheme I proposed.

 

The backup light connection is typically only powered when the vehicle is in reverse.

Please clarify for the TS - - - how does this unpowered line tell the TS when the tailgate is open?

I'm imagining the reverse light can only be active when the key is on; hence, a key switched line. If I recall correctly, OLD cars (back in the 70's and whenever up to the point where they may have changed, there was a "Reverse Switch" in the transmission. When in reverse the switch - I believe - supplied a ground for the backup lights. Under that OLD premises, if the BUL (Back Up Lights) have constant key switched power then there's a beginning of a solution without having to add an additional wire. Still, in my mind I'm seeing the need for another line going into the cab for the ITC Indicator. I'm sure I'm missing your point.

Moderators: This is all for the benefit of the TS. This is not an attempt to hijack this thread. My tailgate locks. And when it's open, if I put the truck in reverse the backup camera looks straight down at the street and the proximity sensor tells me I'm dangerously close to the ground.

I still see just a single grounding switch at the tailgate and a single line running to the cab and providing ground when the tailgate is not fully closed. The ITC Indicator sees that ground, and being accessory powered (or key on) the indicator will light.

 

Please clarify for the TS - - - how does this unpowered line tell the TS when the tailgate is open?

I'm imagining the reverse light can only be active when the key is on; hence, a key switched line. If I recall correctly, OLD cars (back in the 70's and whenever up to the point where they may have changed, there was a "Reverse Switch" in the transmission. When in reverse the switch - I believe - supplied a ground for the backup lights. Under that OLD premises, if the BUL (Back Up Lights) have constant key switched power then there's a beginning of a solution without having to add an additional wire. Still, in my mind I'm seeing the need for another line going into the cab for the ITC Indicator. I'm sure I'm missing your point.

Moderators: This is all for the benefit of the TS. This is not an attempt to hijack this thread. My tailgate locks. And when it's open, if I put the truck in reverse the backup camera looks straight down at the street and the proximity sensor tells me I'm dangerously close to the ground.

I still see just a single grounding switch at the tailgate and a single line running to the cab and providing ground when the tailgate is not fully closed. The ITC Indicator sees that ground, and being accessory powered (or key on) the indicator will light.

Evidently nobody understood the function that I was suggesting, which was a scheme to use that same wire for both purposes, to power the backup light and also to serve to indicate the gate status without losing the backup light power function. Certainly the scheme was a bit complex, and I did not submit a circuit with every part labeled and it's purpose described. But I would expect the concept to be able to be understood by at least a few folks.

 

Evidently nobody understood the function that I was suggesting, which was a scheme to use that same wire for both purposes, to power the backup light and also to serve to indicate the gate status without losing the backup light power function. Certainly the scheme was a bit complex, and I did not submit a circuit with every part labeled and it's purpose described. But I would expect the concept to be able to be understood by at least a few folks.

I understood - its a neat idea and does add complexity, but it works. Here is a simulation: S1 is the backup light switch, while s2 is the tailgate switch. A 100kHz oscillator (eg 555 timer, not shown in detail) injects a 5v peak signal into the backup wire at the cab end via a 10u capacitor. A 10mH choke L1 prevents loss of signal through the battery when S1 is closed. At the tailgate L2 performs the same function.

When S2 is open the SENSE terminal sees almost the same level as the oscillator output. When S2 is closed it shorts the signal to ground and SENSE is close to 0v. This is shown in the lower trace - RED = SENSE and GREEN = OSC. Note that it works correctly whether the backup lamp is off or on, as shown by the upper trace - BLUE = backup circuit voltage and PURPLE = lamp voltage. A simple opamp peak-signal detector is all that is needed to drive an appropriate indicator, an example being shown using U1/U2 below. The trace of the current through LED D2 in the lower pane shows the LED is on when the switch is CLOSED = tailgate open, whether or not the backup light is on.

 

THANK YOU, Irving!! I really appreciate that you even went to the effort of a simulation to demonstrate the function. The frequency was higher than I had picked, but that made the component values more reasonable, thus it was quite appropriate. And the best part is that it will avoid needing to run an additional wire, which can be quite a bother in newer vehicles. And it leaves the outside end, subject to weather a bit, as just a very simple choke coil and a capacitor, two items not that difficult to waterproof.