Meso Map Lights Blowing Fuses

Just got the latest run of Meso Customs map and dome lights. Dome isn’t here yet, but I’m having a hell of a time with the map lights.

Driver’s side blows the dome fuse under the hood every single time I try to turn it on after installing a new map light. I’ve tried every possible variation. Meso even sent me a replacement one in case one of my two was bad. Did not fix it.

Both lights and the replacement work fine on the passenger side, but the driver’s just continues to blow fuses no matter what I do.

Note that is does not kill the map light after blowing a fuse, which is cool that the fuse is doing it’s job. After replacing the fuse and moving the same light to the passenger side it works fine.

Do I have a short somewhere in my wiring?

 

See if the light is touching the metal reflector. A lot of people blow the fuse when they’re installing LEDs, because they touch them against the metal reflector with the map light turned on.

 

I had that thought. I’ll probably just remove the reflectors entirely since I don’t intend to throw the stock ones back in. Will report back with results tomorrow when I pick up more fuses.

 

When I installed mine (I got the very first run of them) I completely removed the reflector with no ill effects. That seems the most logical issue is when you turn it on it's grounding out somewhere in that housing. Did the original map work fine?

 

No dice. Now neither of the map lights work. Not with the OEM bulb or the Meso lights. The fuse isn’t blown this time because the map light still works and the clock is keeping time.

 

Hmmmmmmm what about on the pass side? That's just weird.

 

Passenger is dead too. Not sure what’s up now. I’m beginning to think I’m not meant to have nice things.

 

Oh shit even the OE stuff doesn't work on either side? did you check all the fuses even with a test light? Hmmmmmm wiring, a connector somewhere? sheesh IDK without looking a a wiring diagram and being there it's hard to discern what's going on.

 

I just pulled the overhead console itself and found continuity is good from the plug to the light sockets themselves. That’s about the extent of my multimeter know how, so I’m kinda at a loss here.

Is it even possible to fry the wiring somewhere in the system? Short of ripping the headliner off and following all the wires, I’m not sure what comes next.

 

Do you have a basic test light?

 

I do not. I could probably use on on the wiring harness coming from the vehicle, yeah?

 

You can check for power 12v to the white wire (Pin #1) on the Map Light plug.
The White/Black wire (Pin #2) is Grounded by the Body ECU.
Let’s hope this isn’t the case.

The vanity, dome, and map lights all use an ECU ground.
Are these the ones that don’t work?

@Muddinfun
@Jimmyh[/

 

I removed them because I feared they would touch and short out.

Also never saw any instructions on the MESO site

 

Actually, not quite. The body ECU supplies the ground for the dome light. The white/black map light ground wire connects directly to body ground. The body ECU just happens to use the same ground connections for it’s ground. This is why the dome light fades to off, but if you leave a map light on, it will gleefully shine bright til the battery goes dead.

 

Thanks for the explanation buddy.
I haven’t had my dome light on in years.
I leave it off, honestly didn’t know it would fade out. Lol

I got in the habit of turning all the “extra” lights off after having my 1979 TransAm drain a battery.
Turns out, it was the light in the Glove Box.

 

So would checking the pins on the map light connector for 12v and ground be a good start?

 

Yes. The white wire should be battery power and the white/black wire should be ground. If you have power and ground there, then the problem has to be within the overhead console. Switch, socket, bulb.

 

Snagged a basic test light. I’ll have a go at this here in a bit.

 

The following thread might help.

https://www.tacomaworld.com/threads/dome-light.687510/

There is another fuse under the dash. Also, possible that the circuit traces within the console might have blown.

 

Thank you for the resources my dude. I’m two hours into my 36 spanning today and tomorrow. I’ll read up and have another go on Wednesday.

Hopefully the overhead console itself isn’t fried. Meso had one guy send his in and I hope it doesn’t come to that, but based on the one light I did get temporarily working I know these map lights are worth the trouble lol