[bassett72]

Old on the left, new LED on the right.

 

[riccnick]

Old on the left, new LED on the right.

Got it, thank you, that explains a lot.

Ok so, back to basics here, you definitely tested continuity across the terminals of each light?

If yes (Plus you said they will light up with a bench test), I say you need to clean and crimp the connectors (female blade end on truck) to get a secure connection.

 

[bassett72]

Yes, continuity checks and both sets powered up when I hooked them directly to the battery.

OK, I'll have to run and get some contact cleaner. If I had a little more wire to play with I'd just put new ones on.

I'm still confused as to why they worked before, the LEDs worked for a minute, then nothing?!?!? I'll still clean then, but this is turning into Bizarro world.

 

[bassett72]

Well, I sprayed the contacts, let it dry, still no lights. So, my brain tells me logically if there is power there all the time, then something must tell the lights to turn on when the truck is unlocked via the fob, right? So, that is why I lean towards the computer.... Thoughts?

 

[riccnick]

Well, I sprayed the contacts, let it dry, still no lights. So, my brain tells me logically if there is power there all the time, then something must tell the lights to turn on when the truck is unlocked via the fob, right? So, that is why I lean towards the computer.... Thoughts?

The computer is what connects the path to ground, completing the circuit. If you have voltage, you have a complete circuit already... I'm completely stumped as to why you would have voltage there all the time AND not have the lights work... If you have power there and the lights are good, they should be on. It's very simple in theory, however, as shown here, obviously more complicated than we think. I know I saw the wiring diagram for a 2008 truck with the puddle lights, I'll see if I can find it again and if it shows us anything specific. Maybe someone with more electrical experience than I can chime in as well. My expertise kinda ends after V=IR, lol.

Read through this as it seems like the exact same issue. The guy lists the two fuse circuits as well that you can double check.

https://www.justanswer.com/toyota/3...yota/342xh-2008-toyota-tundra-trim-changing-puddle-led-s-equal-voltage-ect.html

 

[Powertechn2]

From what I recall, some circuits on our trucks are ground switched, instead of power switched, aka positive grounding.


I believe the head lights are this way, but unsure of what else.

I only say this as there is a connector you have to switch around to reverse position when installing plows.

 

[bassett72]

OK, I'm not sure I follow. Is there something I should check? But again, the OEM lights don't work either.

 

[ACDan]

Run a small wire from the negative on your battery to the light and plug on the wire that showed 11v and see if it works. If not, swap wire to positive side and plug up ground terminal to light.

 

[Bob Dobalina]

From what I recall, some circuits on our trucks are ground switched, instead of power switched, aka positive grounding.

.

no No NO!!! NOT positive grounding, that's completely different then having a switched positive. I have worked on many old trucks that were true positive ground so I am like a fuking genius of positive grounded stuff and things

 

[bassett72]

Run a small wire from the negative on your battery to the light and plug on the wire that showed 11v and see if it works. If not, swap wire to positive side and plug up ground terminal to light.

OK, the only way I can get it to light up is by having the negative truck terminal hooked up to the negative bulb terminal and running power from the positive on the battery to the positive on the bulb. Then it lights, but does not turn off.

I guess I think I have the terminals on the bulb pegged right. the OEM bulb doesn't have the posts marked positive and negative. I can play with that more. I also will try the same on the LED, which has a black and red wire to make it easier. have to get the kids to bed first. ;-)

 

[Powertechn2]

no No NO!!! NOT positive grounding, that's completely different then having a switched positive. I have worked on many old trucks that were true positive ground so I am like a fuking genius of positive grounded stuff and things

Fwiw, I only said positive grounding as for some reason a lot of people call negative switching a positive grounding situation.

Not really sure why, but it's what you hear that tends to stick.

 

[ACDan]

OK, the only way I can get it to light up is by having the negative truck terminal hooked up to the negative bulb terminal and running power from the positive on the battery to the positive on the bulb. Then it lights, but does not turn off.

Then you aren't getting a true 11v to the lights.

 

[ACDan]

OK, the only way I can get it to light up is by having the negative truck terminal hooked up to the negative bulb terminal and running power from the positive on the battery to the positive on the bulb. Then it lights, but does not turn off.

Then you aren't getting a true 11v to the lights.

Relay, fuse, wire burnt. Something isnt getting true voltage to the lights.

 

[Powertechn2]

I would connect the puddle light, lock the truck.

Unlock it (the lights should at this time come on), with the light connected, check for power (with the light still connected).

You are likely getting trace voltage, with no amperage behind it.

Which can happen if you have a damaged wire, or if they are driven/powered via ecu, and that circuit has been shorted.

Gotta love trace voltage.

Have a $90 Snap-On test light that measures voltage that I do not use anymore as it had caused goofy readings due to trace voltage in an ecu driven circuit.

 

[bassett72]

I would connect the puddle light, lock the truck.

Unlock it (the lights should at this time come on), with the light connected, check for power (with the light still connected).

You are likely getting trace voltage, with no amperage behind it.

Which can happen if you have a damaged wire, or if they are driven/powered via ecu, and that circuit has been shorted.

Gotta love trace voltage.

Have a $90 Snap-On test light that measures voltage that I do not use anymore as it had caused goofy readings due to trace voltage in an ecu driven circuit.

I can hook up the lights, but they won't work. I'll try checking for power while they are connected though and see what happens. I'll share what I find. It will have to be this afternoon....Check back. Thanks..

 

[bassett72]

OK, on the RIGHT, is where things stand without the OEM lights hooked up----12.06. This is also the same reading when I hook the power to the positive terminal of the OEM Bulb. As soon as I hook up the ground wire to the negative terminal on the OEM Bulb, I get the reading the LEFT----4.7!

I hope that makes sense. Also, without the bulb hooked up, I noticed that when I press UNLOCK, the voltage drops to around 5-6. Then, after the 30 seconds and the truck re-arms, it goes back to the 12.06 reading.

Thoughts?

 

[1lowlife]

I might have missed this but, have you tried testing the hot puddle light wire to a different ground other than the other puddle light wire?

 

[bassett72]

I did, I used the negative terminal on the battery. Is that OK?

 

[Powertechn2]

There is something awry with that circuit.

I can't really say what. I would guess one of the lights shorted internally, causing whatever drives the puddle lights to let some magic smoke out.

Gotta figure out how they get power.

 

[ACDan]

A schematic would help alot. Is there a resistor in this circuit?