HELP Please PARKING, Tail, & License plate lights not working

2018 and 2015 do not use the same bulbs, or wiring, not even close. 2018 lights use 7443N (7440) for signals.

3157 and 4157 are essentially the same.

which switchback set up were you trying to install? this will help us try to sort out what you were doing. if you just stick a 3157 (4157) LED in there it is not going to work, its going to ground or back feed (im not smart enough to know which). The parking light and DTRL circuits are not independent of each other.

a switchback isnt a bulb, it is a system that consists of an external IC to prevent this from happening.

Furthermore, if you are running 4 LEDs on signals you will either need 6 ohms at each corner or 3 ohms on each side in the back so it has enough load to cover all 4. some switch back systems have intergrated resistors already so you would have to adjust accordingly.

 

Get something like this from your local part store and test each of the fuses. It's better than eyeballing.

 

Absolutely, they are a pain to take out and put in.

 

Update.....found a blown fuse at kickplate. Replaced and all works fine again.

 

Actually the SR5 models do use the same bulbs as I bought the 2018 SR5 Housings and my wiring, light sockets, and bulbs went right in without modification. The only difference is they have the LED strips with a completely separate socket that I bought a wiring harness that runs straight to the ignition fuse in the under hood fuse box like the 2017 and below platinum models have. The Limited and platinum models’ assemblies for the 2018 are a different story however and you’re right, they are completely different.

I have no clue on the switchback that I was attempting to use. Some generic from eBay. None of the problem that I asked for help on had to do with the switchbacks at least I do t believe as I removed them several days ago and the issue of no parking/tail lights just happened this am. To answer your question from this morning about the ohms from the resistors that I was using, they were 6 ohms each one for each front switchback.
Based on your username and pic I can only assume that you’re a 737 mech or pilot, correct?

 

Ok now I’m confused, there are THREE different versions of 2018 headlights?!

I’m up front on the triple

 

Yes apparently there are three different ones then. The ones I have are the Black SR5 editions.

Understood, I turn wrenches on the 777, 767, 757, A300, MD-10 & MD-11

 

lol then you definitely know not to listen to me. Must be pretty sick to work on the md-11.

 

Lol I guess so. It has its moments. If you know the systems then it’s easy to work on. Still love seeing that thing go over the fence even though I hate that #2 engine.

 

Which fuse was it?

 

As ask by somonexelse. What fuse

As I am having the same problem