Electrical people please help

[dmurray14]

OK guys,
We have a Chevy suburban, and anyone with a Tahoe/Suburban knows just how crappy the reverse lights are on that thing - to a point where you can't see anything behind you. I set out to fix this problem today - went to walmart and bought a cheap pair of driving lights (fog lights) and plan on mounting them behind the bumper to turn on when the reverse lights come on. I got some wiretaps, but when I measured the voltage at the wire with the reverse lights on, I only get 10volts. This leaves the fog lights a lot dimmer than they should be, and pretty much useless.

What I guess I need to do is find some way to have the reverse light's 10v to trigger 12v to the fog lights so they light up at full brightness (relay or something?) Anyone have any idea what I need to do this?

Thanks so much,
Dan

 

[lightpants]

You are right, you will need a relay.

 

[TechnoKid]

Yeah, you'll need a relay that gets power directly from the battery. Run some 10 gauge power wires from the battery to the rear bumper, then use the 10volts from teh reverse lights as the trigger for the relay. You may want to also add in a switch incase you don't always need the reverse lights on. I'll see if I can do a diagram for you in ms paint or somethign.

 

[dmurray14]

OK cool - so relay it is - but how do I figure out which type I need? Is this something I can get at radioshack?

Thanks,
Dan

 

[lightpants]

Originally posted by: TechnoKid
Yeah, you'll need a relay that gets power directly from the battery. Run some 10 gauge power wires from the battery to the rear bumper, then use the 10volts from teh reverse lights as the trigger for the relay. You may want to also add in a switch incase you don't always need the reverse lights on. I'll see if I can do a diagram for you in ms paint or somethign.

10 Gauge might be overkill, 14-16 should be fine, those lights don't draw that much current. Remember to put a fuse the circuit at the batery as well.

 

[Pepsi90919]

trailer wiring provisions?

 

[lightpants]

Originally posted by: dmurray14
OK cool - so relay it is - but how do I figure out which type I need? Is this something I can get at radioshack?

Thanks,
Dan

I think at radio shack they have them and I think they are called "auto type relay"

 

[Aleksandar]

Dude just get the red wire the black one ( - )
can be anywhere on the chasis of the car it dont matter

 

[NutBucket]

Originally posted by: dmurray14
OK cool - so relay it is - but how do I figure out which type I need? Is this something I can get at radioshack?

Thanks,
Dan

This should do the trick as far as relays go.

 

[lightpants]

Originally posted by: Pepsi90919
trailer wiring provisions?

Standard trailer wiring does not have a reverse light circuit.

 

[myusername]

Standard automotive relay.

$10 is on the high side, but probably what you would pay at autozone/pep boys/advance. I think I've seen them for as low as $3 on the web, but I don't remember where. You will also want correct size blade style connectors and a wire crimper to put them on.

Edit: Wow. I too slow. To make up for it, a linkypoo

 

[dmurray14]

Originally posted by: NutBucket

Originally posted by: dmurray14
OK cool - so relay it is - but how do I figure out which type I need? Is this something I can get at radioshack?

Thanks,
Dan

This should do the trick as far as relays go.

awesome thanks...now i just need to figure out which wires go where!

 

[natto fire]

Originally posted by: dmurray14
OK cool - so relay it is - but how do I figure out which type I need? Is this something I can get at radioshack?

Thanks,
Dan

Yaeah you'll just need a standard 4 prong relay. I don't know how much they cost at Radioshack but I have a whole boat load of them from when I used to work at a junkyard. You can hook the trigger up to the original backup light wire from the surburban. I would think a 10 amp relay ought to do it but you could get a 15 amp just to be safe. As mentioned above make sure to put a fuse at the battery unless you want that wire to become a welding cable should a short arise.

 

[NutBucket]

Originally posted by: dmurray14

Originally posted by: NutBucket

Originally posted by: dmurray14
OK cool - so relay it is - but how do I figure out which type I need? Is this something I can get at radioshack?

Thanks,
Dan

This should do the trick as far as relays go.

awesome thanks...now i just need to figure out which wires go where!

There are 2 contacts for the coil. One goes to ground, the other taps off your current positive wire from the reverse lights. There are two other contacts for the "switch". One wire goes to your battery's positive termina (fused as close to the battery as you can) and the other to the positive of your driving lights. The other wire from the lights you can ground to bare metal.

 

[dmurray14]

Originally posted by: Captain_Howdy

Originally posted by: dmurray14
OK cool - so relay it is - but how do I figure out which type I need? Is this something I can get at radioshack?

Thanks,
Dan

Yaeah you'll just need a standard 4 prong relay. I don't know how much they cost at Radioshack but I have a whole boat load of them from when I used to work at a junkyard. You can hook the trigger up to the original backup light wire from the surburban. I would think a 10 amp relay ought to do it but you could get a 15 amp just to be safe. As mentioned above make sure to put a fuse at the battery unless you want that wire to become a welding cable should a short arise.

Thanks....

They gave be a little fuse holder and fuse in the box, but they had it in line with the ground(?) It seems to me like it would make more send to put it on the 12v wire right up at the battery, right? Can I just use the one they gave me?

Thanks,
Dan

 

[TechnoKid]

30A BOSCH relay

5 pin relay socket

BOSCH type relay wiring guide

On second thought, 12 gauge hookup/primary wire would be just fine.

 

[natto fire]

Yeah but you will want to cut it off of the ground and hook it up at the battery. Just attach the ground from the lights to bare metal on the truck. Try to get a relay that is rated at the same amperage as the fuse.