electrical help...reverse lights delema

[RAndrae]

I have a 04 1/2. I installed a Reunell rear bumper with flush mounted LED lights, one on each side. They don't draw hardly any amps 1 or 2 I believe. I wired each one into the trucks harness that leads to each tail light. When in reverse the stock lights and the LED's come on. They work great!!

Now the problem..... I wanted to put a toggle switch in the cab so I can turn all the reverse lights on when ever I want. I purchased a lighted on/ off switch rated at 15 amps. It has 3 prongs ground feed and load...simple. I ran a fused wire off the battery to the feed prong. I ran a wire from a known good ground to the ground prong and a wire from the load prong under the truck. I was originally going too wire right into the wire leading to the rear of the truck at the reverse switch located on the side of the manual transmission. But Instead I found the correct reverse wire in the loom on the frame rail about half way back and spliced there. I soldered, taped it up all good.......When I flipped the switch all the reverse lights come on.....great!! get in the truck put it in reverse no lights?? WTF Factory reverse fuse under hood blown. replaced it, turn key on, put in reverse, blows the fuse. I unhook the load wire at my new switch replace fuse again put in reverse all works fine... I am stumped. Please help

 

[mwilson]

You want the lights to work when in reverse or when you flip the switch, right? If so you need to do something different.
Calling it a day, but will offer you two different methods tomorrow when I am fresh.

 

[RAndrae]

correct.. I want the lights to work when in reverse or when I use the switch. Looking forward to your help.. thanks

 

[mwilson]

A little more awake now.

After a bit of thought the easiest way will be to purchase a different switch. I will draw a schematic after a bit more coffee....

 

[mwilson]

I will add to this after attaching the picture from my phone. Drawn after only one cup of coffee..

 

[mwilson]

So now I can type without squinting. Where you have already cut the wire I suggest my method above instead of a relay set-up.

Cut the wire under the truck that you spliced into, leave your newly installed "Load" wire attached to the wire going to the reverse lights. Verify that you have the right wire by putting truck in reverse, key on. Make sure that you have power coming through the wire from the b/up light switch. If so, turn key off and make sure that there no power. That will verify that you do indeed have the correct wire. Bring that wire into the cab along with the "Load" wire that you have already added.

You need a switch like I referenced above, you can get a three position which will give you the added feature of no reverse lights at all when in the center position or a two position without the center off feature.

You need the following switch description...

Two position SPDT on-on

Three position SPDT on-off-on

 

[cerberusiam]

Ummm, pretty sure the sense wire from the reverse sensor is the GROUND side of the circuit. Every time the FCM grounds the circuit you are dead shorted, you have no load on the fuse. Do NOT wire directly off the battery into factory lighting circuits or you will be replacing electronic components, like FCM and ECM. Adding extra lights to the circuit is bad enough but don't try to wire in the power feed in back of the FCM like that. You need to wire a ground circuit between the FCM and the PDC and NOT from a battery ground, ground back to a chassis point or you run the risk of throwing garbage into the whole engine\BCM system.

 

[mwilson]

Caffeine study material right here.....

 

[mwilson]

Cerb,

I was wondering that, then thought that an 04 was old enough to not be a worry......but that's why I wanted him to verify the presence of power or not. Figured if he did not get any power then I'd know he was dealing with a ground to activate set-up...

OP, what is the color of the wire that you are tapping under the truck???

 

[lpennock]

The ground wire on the switch RAndrae bought would be for the switch illumination. I.E. so when he turns the switch on it allows the LED to illuminate. The switch would be a standard Single Pole Single Throw if the ground was left disconnected. I agree the Single Pole double throw is the way to go; however I would run a relay on the load side so I didn't need as heavy duty of switch.

 

[RAndrae]

just got up, fighting the sickness that's going around. I thought 04 was old enough to.. to not have the lights etc computer driven. I checked at the reverse switch on the transmission with key off, there is no power. Key on there is power on one side. Same with the wire I tapped into. Only power when in reverse key on. I need to go look but I believe the wire I tapped into is white / green stripe. ** JUST went out and checked on something I was stewing on at 2am...... I have continuity from the LOAD prong to GROUND when switch I added is OFF, which makes sense why the factory fuse is blowing when I go in reverse. If I disconnect the ground prong on the switch I added I just wont have a lighted switch. which I can live with. (like lpennock said) . So I don't seem stupid..... I normally run relays etc and don't rely on high amp switches. But these LEDS I added don't have hardly any amp draw. I figured that the way I ran the added switch would simply mimic what the reverse switch on the transmission does.

 

[mwilson]

Don't seem stupid to me. It is hard to determine how adept someone is on these forums, some people get wiring and some don't.
I would still use my method so the factory wiring before your splice does not get a back feed. Something else may be upstream.
If you still want an indicator you could use a DPDT switch and control an indicator light or two with the extra terminals.

JMHO.

 

[B.G. Smith]

Don't the lights have a hot 12v to them at all times and are activated by ground side. If so then sounds to me like all you need to do is run a switched ground to the reverse wire from the transmission. The reason you are blowing the fuse is the wire you tied into is a ground wire. jmho Stay tuned? bg

 

[RAndrae]

I fixed it...... took ground off switch I added. seems to work fine. reverse lights with switch or when shifted into reverse. answer to B.G. smith...like I posted... there is NO power at the transmission switch unless I turn key on and no power at reverse lights unless I turn key on and shift into reverse. I am going to wire a switch like mwilson suggested. Thanks guys