fuse 15A or 25A ??

[Craig Elliott]

Thor

As far as I can gather from my own car and the S130 wiring diagram in the Lotus manual there should only be one fuse box (the one in the dashboard) with 4 fuses in it. According to the wiring diagram the fuse that relates to the brake lights is the second one from the right. The fuse on the far left controls the:
- map lamp
- clock
- cigar lighter
- glove box lamp
- door warning lamps
- interior lamps
- engine and boot lamps
- horn
- hazard lamps.

The switch for the brake lights is located on the forward facing side of the pedal box as RonR states. These are quite fragile but replacements should be easy to get hold of (they are the same as the switch on the original Mini). As earlier posts have suggested, I'd look at the earthing of the lights first.

Craig

[thor]

OK, good.
Last time I checked one of the fog lamps worked the other one not, because of (NO!, really?) a bad connection.
So if the one still works, I'll check the switch at the end of the pedal box (that was the one I meant earlier..), by connecting the two spade connectors. If the lights come on then, it's a duff switch or the connections to it..

If it still doesn't work, I'll check the connections in the boot...

Or just stuff it all and go for a drive, driving fast enough to keep everyone a good way behind the Lotus....

(actually driving the Golf today, as city driving with 28degrees and no brake lights brings on too much stress....... )

[RonR]

Thor,

So, brake lights and reverse lights don't seem to be working...

Thinking about this, you can discount the "bad earth somewhere at the rear of the car". The brake lights are earthed by the brake light switch, and the reversing lights by the reverse switch through the gearbox. If the side lights and indicators are working, the earthing at the rear is OK.

Fuse 3 must be OK, because you have a working fog light.

That leaves a bad connection somewhere between Fuse 3 and the tail light clusters. There should be 1 or 2 Lucar connectors that join the +ve feeds to the rear light clusters, also there should be a multi-way connector joining the dashboard loom to the rear loom. I would try the Lucars first, these are notorious for corrosion.

Cheers,

Ron.

[schroeder]

Thor

Suggest you use a voltmeter to track down where you have juice. Start at the fuse and work back through the system until there is no 12v signal.

Jason's pic was for an earlier +2S 69-71 I think.

Stu

[types26/36]

The brake lights are earthed by the brake light switch, and the reversing lights by the reverse switch through the gearbox. .

Ron,
I'm not following you there, surely both the brake and rev switch have two connections, power comes in...the switch is activated...power flows through the switch to the bulb....the bulb lights because it is earthed.
If the bulbs were earthed through the gearbox (via the switch) you would need a constant power supply to the bulbs and then when the switch is activated it would earth through the other wire which would go to earth.

[RonR]

Brian and Thor,

My mistake!
Yes Brian you're right, the switches are on the +ve side of the lamps.
I'm guilty of following an assumption to it's logical conclusion

So, given that the rear lamps have a common earth, and the indicators are still working, the earthing must be OK.
That leaves the +ve supply (Green wires) from fuse 3 to the Brake and Reversing light switches, or both the Brake switch to Brake light (Green/Purple) and the Reverse switch to Reversing light (Green/Brown) wires.

Or both switches have failed?

Cheers,

Ron

[types26/36]

[quote="RonR"So, given that the rear lamps have a common earth, and the indicators are still working, the earthing must be OK.Ron[/quote]

Err, Yes, (says Brian putting on his thinking hat which hurts!).......and providing the bulbs are making good contact in their respective sockets.

[thor]

And my head hurts from my trying to understand with my own ignorance and limited electrical knowledge, but I will endeavour to find out all this tomorrow!

(after spending the day on the beach in the forecasted 28 degrees--- WHAT?! beaches in Norway I hear you say? Yes, illogical but true... )

[twincamman]

a simple finishing nail in the offending fuse receptacle reveals the offending circuit so it can be rewired ----though not an accepted method of trouble shooting ======it works after a fashion ---and after rewiring an ?lan and a Europa the odd electrical fire is not nearly as traumatic as it once was -----ed

[thor]

After checking the wiring diagram, it seems (correct me if I'm wrong!) that the fuse no.2 from the right works the reverse light, brake lights and fog lamps. If none of these are working then it's most likely the fuse, OR the connections behind the fuse box, right? Will the fuse box come out, or is there any chance of access WITHOUT taking out the dash, which I'm not doing, I'm telling you!

Is my asssumption correct? Otherwise I'll just keep driving fast enough not to have anyone close behind me......

[RonR]

Hi Thor,

Yes, 2nd fuse in from the right = 3rd from the left!

If your fog/spot lamps are working, the fuse must be OK (unless some DPO has rewired them) you just need to remove the fuse and try the fog lights to check.

There are 2 feeds from that fuse, the first goes to the fog light switch, the second runs into the engine bay. On my loom (a Chris Neil S130 replacement), there's a multi-way connector behind the dashboard close to where the loom feeds through the bulkhead. On the engine bay side of the conector there are 2 green wires joined together, one to the Brake light switch, and the other to the reversing switch.

Personally, I would check the following things, assuming that my replacement loom is close to the original one that you have:

1. Check that the fuse really is supplying the Fog/Spot lamps.
2. If the Fog/Spots work with the fuse out, they have been rewired in some other way, so you need to check the +ve supply to the fuse:
2a. Check that there's ~12v at both ends of the fuse with the ignition on.
2b. If there's ~12v at only one end, the fuse has blown.
2c. If there's no reading at either end, the problem is on the supply side, the white wire between the ignition switch and the fuse. Check the in-line connections to the ignition switch first (there's less work to dismantle the cowling).
3. If the Fog/Spots only work with the fuse in, the fuse must be OK, so the problem is "downstream".
3a. Check the green wire between the fuse and the multi-way connector, and also check the connections inside the connector.
3b. If you don't get a reading at the connector, I'm afraid you have to dig deep and check the fuse box end.
3c. If you do get a reading at the connector, check the green wire to the brake light switch in the engine bay.
You should have ~12v all the way from the fuse to the switch.

One thing to watch for is where the loom passes through the firewall. It has been known for the grommet to split, and the wires to rub against the abrasive glass fibre.....

Cheers,