Hi
I'm trying to diagnose my "no reverse lights" problem (1989 Civic DX Hatchback)
Car engages reverse, no light comes on
New bulbs, still nothing
Switched the "back-up light switch" for a known good one
Still nothing

Could be a ground issue, how do I tell?
Ground wires between the two tail lights have never been touched, factory tape still on them (the gray stuff)
I have no other light issues other than this. Getting a new battery for my voltmeter to see if there is voltage from the two wires from the harness, so I will know tomorrow.

Is there a specific fuse for this circuit? I'm looking at the shop manual right now, not very helpful.

 

I have the same issue on my 91 hatch.

 

i would have guessed fuse but iirc you said no other lights were having issues and usually reverse lights are tied with some other lights in the Fusebox

check the fuse section in the Faq

 

Check the connectors by the trans. When my reverse lights weren't working, there was a connector by the trans that had come undone. Might help your situation.

 

for the sake of simplifying things, i took the reverse switch out of the trans, and connected it.

to simplify my problem further, i connected the two plugs from the harness together, to see if my reverse lights came on. even with the car started, no reverse lights. some red lights came up on the dash however.

gonna be ripping stuff apart checking for continuity today.

 

Same **** here on my civic iv done all the same things

 

i found the solder on the terminals to the switch itself break. i had to resolder the terminals. works fine now. just be careful. stuff is fragile around there. you dont want to break the terminal off completely.

 

I tested the continuity at the switch, using a 9v battery and a test light. looks good while pressed.

Tested to make sure the yel wire has continuity to ground, good there. not on the green one. put the bulb in, no good. can light the bulb up with my 9v though.

Went to the reverse plug, tested continuity between the ground wire and the chassis, good there.

connected the green wire and yel wire terminals for the switch, went back to the tail lights, tested continuity between green and ground, no good. so it's somewhere in the chassis. still looking, i'll keep posting what i find out, lots of people have this issue so far.

 

checking the engine harness now...

engine side plug and plug that goes to the cabin
engine side: no continuity between green/blk and ground. short somewhere in the engine harness??? going to grab a new harness from a junkyard and see if that helps.

 

So how many volts are you getting at the light? How many volts are you getting at each connection point working back from the bulbs? Test light is not sufficient.

 

No continuity means an OPEN not a short.
That is GOOD that you don't have continuity to ground on the GRN/BLK.

Do some voltage tests on the wires at the tranny that plug into the reverse switch.

You should have 12v on the YELLOW wire *ALWAYS* when the ignition is turned to 'ON'.

Then you should have 12V on the GRN/BLK when you shift to reverse.
That GRN/BLK goes all the way to the tail lights.

Assuming you have power on the YELLOW and then power on the GRN/BLK at the tranny -
Shift to reverse with the ignition in the ON position (engine not running)
Test the GRN/BLK wire at the tail light for 12V.

If you have power in all 3 of those places, then do a continuity check.
Check for continuity to GROUND on the BLACK wire at the tail light.


Check this out...

 

checking out that wiring diagram now.
so what i did is i tested continuity of the yellow and the green wires on the engine harness. there is no breaks there. if i connect the green wire to the yellow wire and run 9v through it, there is no light, meaning the break is somewhere in the cabin. next step is to unplug the harness from the fuse block to test from the engine compartment to the fuse block. going to test tail light harness the same way as well.

i don't need a voltmeter for this.

 

tail light harness was shot.
replaced it with one verified to work, no lights still
tested from grn/black at the switch, all the way back to the reverse light socket. grn/black is not broken. the yellow wire is, somewhere.

 

Probably something with the wiring leading to the lights or the computer, i know in automatic to manual conversions you need to mess with the computer in order to have any reverse lights.

 

this was a lot simpler, but stupid.
for whatever reason, the grn/blk on the engine-cabin harness connector was in the wrong spot.
put it to the right one, tried it out, nothing.
one of my LED bulbs went bad... i use them for reverse lights
so it was a failed tail light harness, and a failed LED bulb.
it's all working good now. Ready to pass inspection. Thanks for the ideas you guys, and for that wiring diagram.

That bulb definitely started failing during this experiment however. Depressing!

 

yeah, i know a voltmeter would be nice.

basically i made a 9v test light out of a battery and a regular test light. some things, i had no clue what i was talking about.

tail light harness is shot. connected one end of my tester to the grn/blk in the bulb socket, and the other end to the grn/blk in the plug of the tail light harness. no light came on, replaced with a different one i tested first. but yeah, bad bulb, ha ha. it's been a long day.

 

Does it matter which wire is soldered to which terminal? If so, what is the correct way? Thanks!

 

I think it's just a switch. So I don't think it matters.