1800: 1971 E. Rear brake light repair (is this wise?)

[ChasesDragons]

Hi all,
The rear nearside light seems not to be working. The brake and indicators are fine.

Looking at Warren Townsend's wiring diagram (Thank You!), The two rear lights (side lights?) are fused separately via 11 and 12.

Would it court disaster, to splice the lights together, using the working side's supply?

I checked the wire to the non working side, it is only supplying about 0.4V...which I assume is near as dead. The other side is a healthy 12+V.

This is a short term repair of maybe 3 months.

Regards

[Clan]

Originally Posted by ChasesDragons

Hi all,
The rear nearside light seems not to be working. The brake and indicators are fine.

Looking at Warren Townsend's wiring diagram (Thank You!), The two rear lights (side lights?) are fused separately via 11 and 12.

Would it court disaster, to splice the lights together, using the working side's supply?

I checked the wire to the non working side, it is only supplying about 0.4V...which I assume is near as dead. The other side is a healthy 12+V.

This is a short term repair of maybe 3 months.

Regards

It shouldn't be too hard to trace that bad wire in the loom all the way down to the light switch where it will meet up with the other side I guess at the fuse box . Do the 2 front side lights and right tail light work ok?

[c1800]

Originally Posted by ChasesDragons

Hi all,
The rear nearside light seems not to be working. The brake and indicators are fine.

Looking at Warren Townsend's wiring diagram (Thank You!), The two rear lights (side lights?) are fused separately via 11 and 12.

Would it court disaster, to splice the lights together, using the working side's supply?

I checked the wire to the non working side, it is only supplying about 0.4V...which I assume is near as dead. The other side is a healthy 12+V.

This is a short term repair of maybe 3 months.

Regards

It’s not clear to me if you’re saying the side light is the one that is not working as your Topic title is “brake light repair”. Then you indicate that the “Brake and indicators are fine”.

EDIT: unless your car came from N.America you likely don’t have “side lights” as shown on the diagram and the pic below. So your problem is with the “rear light” as it’s described on the diagram ?

[ChasesDragons]

Originally Posted by Clan

Do the 2 front side lights and right tail light work ok?

The RHS front and side and tail lights work.

The LHS front and tails do not. This is what led me to the fuse. I haven't even checked the fuse. The vehicle was taken in previously to get the rear tail working. It doesn't now...and I don't quite know how to diagnose!

[ChasesDragons]

Originally Posted by c1800

It’s not clear to me if you’re saying the side light is the one that is not working as your Topic title is “brake light repair”. Then you indicate that the “Brake and indicators are fine”.

EDIT: unless your car came from N.America you likely don’t have “side lights” as shown on the diagram and the pic below. So your problem is with the “rear light” as it’s described on the diagram ?

Nope, you are entirely right, I haven't played with any of my classics for 10+ years. This has turned me into an illiterate.

It is a UK car and yes, you are correct. It is the rear light and the front..light that carries a "side light with indicator" ?

Thank you for correcting this, as they say, the quality of a question is entirely dependent on the clarity of the question!!

[Derek UK]

Still waiting for the fuse check but would also say to confirm a good earth to complete the circuit. When the earths are made via screws into the bodywork metal they can fail due to rust. Not unusual on old Volvos.

[gjr0]

I'm a firm believer in letting fuses do the job they were designed to do, so I would not splice the output of fuse #11 and #12 together.

Fuses #11 and #12 are the same rating. What happens if you swap the output wires ? Does the problem change sides ? Do you have a Volt Ohm meter (VOM)? If so, you should have 12V input side of both fuses. How about the output side ? At the connector where the wire to the lights slips on ?

I had problems with the connections in the fuse block being internally corroded (between the riveted together parts), causing all kinds of intermittent problems with the lights on a 220.

[Derek UK]

1971 1800E wiring diagram. Note that the number plate lights look to run via the #11 fuse so if they are working check #12.

[ChasesDragons]

Originally Posted by gjr0

I'm a firm believer in letting fuses do the job they were designed to do, so I would not splice the output of fuse #11 and #12 together.

Fuses #11 and #12 are the same rating. What happens if you swap the output wires ? Does the problem change sides ? Do you have a Volt Ohm meter (VOM)? If so, you should have 12V input side of both fuses. How about the output side ? At the connector where the wire to the lights slips on ?

I had problems with the connections in the fuse block being internally corroded (between the riveted together parts), causing all kinds of intermittent problems with the lights on a 220.

That is a great series of trouble shooting manouvres. I do have a Digital Multimeter (hopefully we are talking about the same meter?) I will put it to good use. I did not think about swapping things at the fuse block.

Originally Posted by Derek UK

1971 1800E wiring diagram. Note that the number plate lights look to run via the #11 fuse so if they are working check #12.

Oh hello....that's interesting because the Number plate lights were working....WTH is going on??!

[ChasesDragons]

Ok,
This is embarrassing. The fuse was blown and I poo'd myself and thought that the Norse God's had it I'm for me again. Thank you all for patiently assisting...again!!

U