Reverse light issues (1 Viewer)

[Fandrover]

Well that didn’t last long till a new problem showed it’s ugly face!
Jinxed it well and good with my electrics next comment in the last thread!

So,
1st stage was a few weeks ago noticed that with engine cut off but not retarding or removing the key that the reverse light was on. Retard key position and remove and it went out. No problem I thought, maybe it’s meant to do it as a reminder and I’ve never noticed before.

2nd stage was on completion of changing the clutch cylinders a couple of days ago I noticed the reverse light was permanently on no matter what I did.

3rd stage I removed the glass fuse gave it a clean, refitted and great no reverse light permanently on.

4th stage decided to check it is actually working and boom it seems I now have no reverse light regardless of key position, engine running or not, gear selected in reverse or anywhere else!

So yet again I’m here asking for experiences, opinions, suggestions, photos!
It was due to go for inspection today but I’ve postponed until I get this fixed

Thanks as always in advance

 

[South Texas 97]

Always put the year and model of your truck somewhere in the message. Makes it easier to provide advice.
in my 76 FJ40 I found the entire rear harness to be a mess. There is 12v going back to the reverse switch, which in my case is on the gearbox. And from there back to the reverse lights. There had been a short of some sort, or animals chewed the wires, insulation was almost completely gone on a couple of wires. But everything still worked, most of the time. Take a look at the reverse switch wiring and then follow the harness along the frame rail.
do you have the wiring diagram available. ? They are on the forum, or on Coolermans site.

 

[DangerNoodle]

Sounds like a ground issue, possibly. Could have had something back feeding through the lights keeping them on, and now a ground is fully disconnected which is why they won't turn on at all.

Just a guess, but I would ensure everything is grounded well, a notorious problem on a lot of 40s.

 

[Living in the Past]

Sounds like a ground issue, possibly. Could have had something back feeding through the lights keeping them on, and now a ground is fully disconnected which is why they won't turn on at all.

Just a guess, but I would ensure everything is grounded well, a notorious problem on a lot of 40s.

Unless there a positive lead in the harness to the back would hard for this to be a ground issue. Not saying it's not.possible just not likely. The 4WD light on the dash for the vacuum operated 4WD the bulb fits into a plastic isolator because the switch on the transfer case is providing ground when in 4WD. The reverse light switch controls the positive side. First I would do it disconnect the wires on the reverse light switch. Could be a couple of places depending on year, model and import market. Original poster is in Portugal.

 

[Fandrover]

Hi all, with a history of chasing ground issues I was hoping I was desperate to avoid it again.

Hence the desperate hope that the strange immediate effect of taking the fuse out and replacing it would identify something else to someone.

Vehicle is a Hj45 1978 (maybe 79, still trying to be certain)

 

[pb4ugo]

If it worked b4 you fooled with the fuses. I would start in that area. Its probably domething simple. I think the wire going to the reverse light switch is hot with the key on. Powers goes thru the switch when in reverse. So the ground would be at the reverse light.

 

[Living in the Past]

Vehicle is a Hj45 1978 (maybe 79, still trying to be certain)

If the tank is inside the cab you would have a 78. Under the cab a 79. Being a diesel should also say if it's 12 or 24 volts. Depending on climate would be one or the other.

 

[Fandrover]

If the tank is inside the cab you would have a 78. Under the cab a 79. Being a diesel should also say if it's 12 or 24 volts. Depending on climate would be one or the other.

Thanks for that info, in which case definitely a 78 12v

 

[Fandrover]

If it worked b4 you fooled with the fuses. I would start in that area. Its probably domething simple. I think the wire going to the reverse light switch is hot with the key on. Powers goes thru the switch when in reverse. So the ground would be at the reverse light.

Cheers and yeah that was my thinking. The only bit that threw me was that fuse is shared with the turn signals which Havnt showed an issue... So I guess the likely suspect would be the ground, but that still asks how taking a fuse out then in changed it from always on to always off.

Darn I hate electrics! It's like a living beast that moves around

 

[South Texas 97]

Think of it more like water running through pipes, not so scary.

 

[Fandrover]

Not a huge update but at least narrowing down options…. Fuse box, wirining, reverse/backup switch are on the culprit list as bypassing all with a direct feed to a rocker switch then to the reverse lights works perfect which was enough to get through an inspection!

Will update next time I get chance to play in between building my house!

 

[sggoat]

Sounds like a ground issue, possibly. Could have had something back feeding through the lights keeping them on, and now a ground is fully disconnected which is why they won't turn on at all.

Just a guess, but I would ensure everything is grounded well, a notorious problem on a lot of 40s.

Of course--remember "Claudia's Admonition"---"it's a ground issue"