'99 Mazda 626 tail lights out

E

ekmdgrf

Joined
13 Jan 2012
Messages
659
Reaction score
62
Location
Blackpool
Country
United Kingdom
Seems that the tail lights, side lights and dashboard light are out on my 99 Mazda 626 Phoenix. I've checked the 15A fuse in the engine compartment and it lacks that continuity one would usually expect. I replaced the fuse and the lights came back on for about 500ms before the fuse again underwent an existential failure. I suspect that this may be water ingress attributed to a weekend of driving through water in Wales. I've given a rudimentary inspection of the tail lights and side lights and can't see any evidence of water ingress. Plan is to wait until the weekend and see if it dries out and try again. Is this a fair course of action or am I likely making canine vocalisations towards some incorrect lumber? Does anyone know if the vehicle is prone to water ingress in any given area? If all doesn't turn out well at the weekend, what should one try next?

Thanks.
 
Sponsored Links
What I used to do with an almost impossible to find fault when I was in electronics was to put an exceedingly heavy fuse in and then look for the smoke, it was an exceedingly quick way of finding it but you could of course set your car alight so I wouldn't advise it.

Check by looking at the lights with someone inserting the fuse and see if any of the lights are dimmer than the others or don't come on at all, if they stay on long enough. If it works the problem will be somewhere in that region.

Peter
 
Sponsored Links
Peter.N. said:
What I used to do with an almost impossible to find fault when I was in electronics was to put an exceedingly heavy fuse in and then look for the smoke, it was an exceedingly quick way of finding it but you could of course set your car alight so I wouldn't advise it.

Check by looking at the lights with someone inserting the fuse and see if any of the lights are dimmer than the others or don't come on at all, if they stay on long enough. If it works the problem will be somewhere in that region.

Peter
Click to expand...

Brilliant Peter :D Nicely old school :D
John :D
 
Have any bulbs been renewed recently - or possibly removed and reinserted in the wrong holder?
Seriously. the car lamps should withstand rain - and should have dried out anyway by now. Do check the wires to the front sidelamps for melting though.
John :)
 
You are using the correct replacement fuse size (amperage)?

Disconnect each light cluster at a time, checking between each one.
If still no joy wiggle the wiring loom to see if you can get a short to the steel work from a wire/connection block. You may have a sidelight relay, pull it out or replace it with a similar relay in the fuse box and retest.
It will probably be something at the end of a wire run, like the light in the boot, Door entry light, or the like.

Have you lost all sidelights or just two?

You will need a box of fuses ...........
 
No bulbs have been removed or replaced.

It wasn't really a little rain. There was water flowing across most of the roads, a river flowing across the front lawn of the B&B I was staying, with the owners having a rescue a car from a ford that I was (mostly) able to negotiate and every building I visited lost power while I was there! It wasn't great weather!

It is definitely the correct fuse. I removed a 15A fuse and replaced it with a 15A fuse. The original, to the best of my knowledge has been there for 14 years. The replacement was robbed from another circuit in the fuse box.
 
I've spent a rather frustrating day messing around with this. Seems that a good place to start prodding with a multimeter would be the TNS relay but I'm having a devil of a job locating it. Seems that the wiring diagram I have is for the US model and the colour scheme is radically different. Does anyone know where one can locate the TNS relay? Also, where I can find a decent wiring diagram with the colour codes of the wire?

Thanks.
 
If you have a good multimeter you could measure the resistance to earth from several points in the circuit that's faulty, the reading will only be a few ohms at most but the nearer to the fault you get the lower will be the resistance reading.

Peter
 
Got the meter on it and had a fiddle around with the various lights and wires. Problem went away. Great. Only it came back when I shut the boot. After a bit of opening and closing, it seemed to short when the boot is locked. Took a look at the lock mechanism and there's a wire coming from it. Presumably the sense wire for the alarm? The wire had a terminal connector on it, so I pulled it apart to disconnect it. Sure enough, locking and unlocking the boot then had no effect on resistance. Not entirely sure how that wire works. Surely all that can be done to it is that it's grounded at some point, which if it's chaffed against the tail light wire would open up a short when it's grounded. Not sure why it shorts when it's connected from the lock though?
 
Check the wiring where it goes from the tailgate to the body inside a rubber boot, the wire can break and cause a short.

Peter
 
You must log in or register to reply here.
Sponsored Links

Similar threads

S
Heatline Compact S24 boiler issues
Replies
2
Views
3K
Sinnerman
S
Back
Top