Trunk Light Circuit. Easy Peasy Lemon Nawwww?

[Nuclearbacon]

Hello DMCTalk!

I am chasing a few electrical gremlins and this one should be so easy, but it's eluding me.

My car has never had a functional trunk light, glovebox light, or engine compartment light

The engine compartment light switch is crumbled. Haven't gotten a new one, I don't believe its messing with anything, not concerned at this time(?).



Looking at my schematic in the shop manual (above), I figure I should attack the trunk light first, it seems the easiest. I have done the following:

0) I do not know what A or B are... I just realized they are wire colors. Ok!!
1) Purchased a new white trunk switch. Confirmed functionality: Ok! (old one also was crumbled plastic)
2) Black wire coming from trunk-light-switch-hole goes to ground, checked continuity at another bolt, has good ground.
3) Checked continuity of purple/white wire that travels up to light from trunk-light-switch-hole: Ok!
4) Checked continuity of purple/white wire that travels up to light from trunk-light-switch-hole through the light and at the metal bracket at the end of the circuit (still at the light):Ok!
5) Checked bulb. Lights up! Ok!
6) Checked for voltage at purple wire at bulb at center of trunk: 0V nothing.
7) Checked fuse 12: Good: Door lights also function.

This also gets me into another area which I personally messed up:

The interior rear luggage compartment light (which I have never messed with) Works when you rock it back (the position for always on). Rocking forward does nothing.
9) Door ajar light works and door lights come on and off with switch.
10) I have purchased a NEW front light and have wired it in the following way:







I did discover that all 3 of my interior light diodes are shot (no continuity on any of them in either direction) because of my stupidity. well, lack of knowledge I'll call it.

Ok story time.

I had functional dimming interior lights when I purchased my car. Then my front dome light bulb died. I went to take the bulb out and the entire housing crumbled in my fingers. Just disintegrated into plastic dust. DMC didn't have any yet, so I ordered on ebay from some seller that had one that looked correct. but the contact posts were in a different orientation. Not knowing the order, I plugged them in thinking the same way the other one was, and flipped them on. They went on for a second, then dim then nothing. Including my door lights. nothing. My #12 fuse was blown. And I think this is when I blew my diodes. So! I found another post where someone split the $8 diodes open and literally they are a soldered diode to two terminals. (I currently have a 200 pack for $8 on its way) so I'll make three new ones. (why are they three different colors?)



SO! before my bulb changing screw-up, I didn't have a working trunk light. What I'm curious about is this: Did my interior lights screw up something else within my trunk lights? It looks like they should be on different circuits but I know they get 12v from the same source/fuse. I don't think this is what has happened, but I'm curious.

Where does the purple wire go after it disappears from the bulb in the center of the trunk lid? is there something else I'm missing and the trunk light/glovebox light/engine compartment light all not functioning says that I've got a bad _____ ? Do all three bulbs not functioning give someone a clue I'm not seeing?

Also looking at the engine compartment light diagram there are extra things too..



What are C and D? Oh and I'm completely rebuilding the brakes too. splitting all the calipers, new master cylinder, all sorts of goodies. But that's another post

Thank you for your insight!

[Nuclearbacon]

I found this which explains the colored diodes... even though they are all the same part number and rating?



I realize I've kinda gone all over the place here... I really want to understand the wiring. Thank you!

[Bitsyncmaster]

I'm pretty sure all the diodes are 1 amp rated and the different colors are just to help the installers of the harness follow instructions. So making new diodes use a 1 amp or greater part.

The purple wire always goes to the bulb connector that is always connected on one end of the bulb. The switched ends have the black ground wire and the purple white wire.

Some of the dome lights you buy on line (not from vendor) are different and have a diode inside which needs to be bypassed.

The hood and engine compartment lights go though connectors in the harness which may have connection problems.

[Nuclearbacon]

Dave thank you! I also received your email about the RPM relay, thank you for that as well! I believe I have a harness problem as the always-on purple wire at my trunk light bulb has 0 volts. Where would that wire terminate in the harness? Trunk light to.... somewhere in the fender or where the wiring harness disappears into the front fascia?

I'd love to know where that plug is! On the main wiring diagram for the car , (the poster DMC puts out) there are about 4 purple wires that ALL go to one point. (see below)



Now to follow that purple wire out of my trunk and back to the fuse block.

[Bitsyncmaster]

All the wires in the front go to two connectors in the washer bottle area. A pain to get at.

[Jonathan]

The connection for the frunk light is behind the grill. Pull it off (carefully) and you get easy access to see what's wrong with it. Sorry, don't have a good pic handy or I'd share it with you.

[Rich]

Handy photo here - the purple wire and black wires and their connectors seen behind the grille.

IMG_8457.jpg

[Nuclearbacon]

OK! Thank you for the pic! Would that connector be the dot on the wiring schematic? I'll be pulling my grille tomorrow to take a look!

[Rich]

....Would that connector be the dot on the wiring schematic? ....

That connector is likely the oval on the P wire shown in quadrant I3 on the schematic, not the dot you point to in post #4.

Expect to see a P wire on both sides of the grille connector.

[Nuclearbacon]

Gotcha! I didn't even notice those on the diagram. What is the dot I'm pointing at then?