Attempted reverse light upgrade, Houston we have a problem!

[Slowgoat]

Put some more powerful bulbs in my reverse lights pretty much exactly like this thread shows:

886 Backup light mod - Tacoma World Forums

It is an 04 v6 sport.

As soon as I put it back together, the reverse lights stopped functioning.

I have a reverse camera, it doesn't sense anything when I go into reverse (not surprising).

Fuses look good, one under the dash, one under the hood.

Hazard flashers work, ac controls, turn signals and rear wiper controls are out.

Put it all back together with stock bulbs, and still no go.

Continuity with the bulbs is good. All the bulbs test ok. Old bulbs should work, but don't.

I moved the bulbs around in their sockets endlessly trying to get contact while the bulbs were in place, also.

Thought I'd ask you all for some hints.

I'm thinking it could be the reverse switch on the transmission, which doesn't make sense. Or a relay?

Does polarity matter on the bulbs?

Cold I run a jumper from the battery? Read about it but never tried it.

I have a brand new multi meter, and am wanting to learn how to use it.

All Bulbs and stock bulb holders look good when I tested their resistance in and out of the bulb holders.

What is the next step?

 

[fourwd1]

Use your brand new multimeter to see if 12V is getting to the socket when you're in reverse.

 

[Slowgoat]

Will do, thank you.

 

[Misterquad]

For grins, I would replace the fuse.

 

[Slowgoat]

Replaced fuses, no change fogs are out too. And it is only the rear wiper that is out.

 

[Fern]

Sounds like a relay. Look for the fog lamp relay. Replace or see if there is an identical 1 you could swap it out to test it.

 

[Slowgoat]

No fog light relay, did the fog light mod.

I'll throw the old relay back in there and see.

Worth a try, and a good idea.

 

[Slowgoat]

Swapped relays, and undid the mod. And fogs work again.

The mod works by running a jumper to the spot on the under hood fuse box that says "IG".

Also checked for voltage at rear taillight assembly, got voltage for brake lights and flashers, nothing in reverse for back up lights.

It has to be where I tapped into the head unit (the reverse wire) or the switch on the transmission?

Thank you everyone for the input.

Can't wait to figure out this mystery.

 

[Fern]

So were all the fuses good when you checked before? Check again after the relay fix. Just my 2cents.

 

[Slowgoat]

IG1 fuse 15w.

Bingo!

That is the answer!

Thanks!!!

 

[Fern]

Glad it worked out!