Beginner Electrical Questions

My landy is a negative earth 1969 2A with lights in the front wings. I'm putting her back together for some test runs this summer after a lot of mechanical work. The electrics were an unknown state when I bought her so I'm just testing things now and working through problems. I am a complete novice to vehicle electrics.

Brake Light

I couldn't get the brake lights to illuminate. I have an old Lucas switch on the brake pedal. I measured the voltage across the contacts in one of the brake light fittings and got 2V when the side lights were on; the smaller filament was lighting up; but no voltage at all when I pressed the brake pedal and disengaged the push-button switch mounted on the pedal.

I connected the brake light's feed directly to the battery feed and both filaments lit up so the bulb and fitting are ok. I measured continuity on the brake pedal switch and it appeared to be working correctly. To double check I connected the G and G/P wires going into the switch together to eliminate the switch completely, and the brake lights came on..

It looks like I have a faulty switch and need a new one, but I don't understand why it appeared to be ok with the continuity check but in practice it's not carrying voltage when switched. I did the continuity check with my multimeter, it beeps when your probes are joined continuously between, for example when a switch is bridging contacts correctly. Or that's what I thought I was doing anyway..

Right Indicator

Right rear indicator (front wings are still off at the moment..) is inconsistent. It works 9 times out of 10. Connecting earth straight to battery with a long test lead does not help so not a faulty earth I think. It either works when you indicate, or it won't. If it won't no amount of jiggling the switch in position or moving wires will get it to work. You switch the indicator stalk back down and on again until it takes and then it works fine.

I can't get the left side to fail like the right does.

Indicators are wired to my amber ignition light mounted on the dash which goes on and off with the flasher when it's working. When the right indicator is not working the ignition warning light stays off.

On the wiring diagram the flasher unit only has one output so if I understand correctly and the flasher unit was at fault the left indicator would fail just as often? I currently suspect my indicator stalk's right hand switch. What do you think? Not sure how to test other than taking it apart and swapping the left/right contacts to see if that makes the left side inconsistent and the right always work..

Tail Lamp

My new tail lamp needs bullet connectors rather than the lucar that my previous one needed and that are on the wiring. The smallest bullet connectors I could find in Halfords were red 5A ones and they seem too big to fit in the tail lamp's connectors. What kind of bullet connectors do I need?

I can’t help too much as this sort of thing is really a process of illimanation piece by piece.

For your brake lights that sounds like a classic earth issue or dirty contacts in the bulb holder.

Is your fuse box all good and clean. All the earths good for any issue. I had an issue once that gave a continuity “bleep” but only 2 volts, burnt fuse holder.

Oh and a stupid question they are the correct bulb holders and you are not forcing bulb in incorrectly?

I take it we are not talking LEDs?

As for the bullet connectors you may need to buy the solder brass bullets if the crimp ones are wrong size and where you are trying to plug into is original, (guess) pics?

Good luck. You will get there

J

https://www.altecautomotive.co.uk/c...ype-auto--electrical-connector-47mm-600-p.asp

Like this?

J

Sorry to say this but at 50yrs old I would be fitting a new loom, updating the fuseboard and getting some relays in there for the headlights.

Continuity was confirmed but too much resistance to illuminate the lamps.

The bullets you linked to look like they might fit. I can add insulation myself with heat shrink and I am happy to solder them if that type is not crimpable?

For the brake lights, with the switch in the circuit the brake lights do not work, with the switch removed from the circuit the brake lights do work. The 2V I reported lighting the smaller filament in the tail/brake bulb when the side lights are might have confused matters - but it's my understand this is expected since the voltage regulator steps the tail light circuit down to 2V to suit that smaller filament. When the brake light circuit completes 12V is passed to the bulb and both filaments are lit. This is exactly what happens when I remove the brake switch from the circuit.

What you say about your continuity testing and fuse holder is interesting but I don't think it's my problem. Even if this stepped it down to 2V the smaller filament would still light, as for when the side light circuit supplies 2V to the same bulb. It's also the same fuse protecting my indicators and tail lights which are all lighting up at full strength (when they're working correctly, suspect indicator switch to one side for now ).

But I am a complete beginner so I'm going to listen! I'll try supplying a direct earth from the battery with a known good test lead, and I will clean up the fuse box as best I can, it's pretty filthy and has lost its cover a long time ago..

dieseldog69 said:

Sorry to say this but at 50yrs old I would be fitting a new loom, updating the fuseboard and getting some relays in there for the headlights.

Continuity was confirmed but too much resistance to illuminate the lamps.

Click to expand...

Yes she definitely needs a new loom dieseldog. The plan is to learn about how the wiring works by fixing up the existing gremlins and sorting out any mess or bodges I can find and then do a re-wire perhaps over this or next winter when I'm more familiar with how things work.

"Continuity was confirmed but too much resistance to illuminate the lamps." <- well worded and that adds some light to what marjon was saying I think. switch contacts working well enough for the continuity test but contacts too dirty to light the lamps?

Don’t know the system re the reduction to 2v.

As I said it’s just a matter of working through 1 system at a time.

Most of it is really straightforward just follow the 12v path on each.

And as @dieseldog69 said don’t be surprised if the problem is in the middle of a loom somewhere.

The bullets are easy to solder no need for shrink if fitted properly

I am sure you have a wiring dia (sure I saw you asking earlier) if not it’s a big must have.

J

Don’t use “continuity” (it’s a diode test really) for trying to test a circuit, it’s for testing diodes. If you switch to resistance and measure the switch you will find out why it’s not working. It could show good on diode tests, but be over 8-10ohms of resistance. 12 ohms would give you 1A at the light, probably not enough to illuminate it.

The bullets you need a what classic car places sell. They are solid brass. I would get ones for 2mm wire, as these can be soldered to smaller wires, but you shouldn’t any larger that need the bullets.

Cheers Mick. Yes, very high ohms on the old brake switch so I will be ordering a new one. And I've done this on two other switches today very useful..

Panel Lights

Having tested both the panel light bulbs OK I looked at the switch. One of the spades was wobbly. With the switch on I measured the resistance across the two spades with and without holding the loose one "in position". Infinite ohms with the wobbly spade sitting loose, changing to very low resistance when I held it up a touch with the probe. New switch needed here then!

There's another problem with the panel lights I haven't fixed yet.. and I'm afraid may not be able to before a full re-wire(!). With the switch out of the circuit I completed the circuit manually and just heard a clicking from the other side of the bulkhead! I don't have a helper (chocolate labs don't count for this kind of work ) so I can't pinpoint where the click is coming from.. There's an old style fuse box and the expected voltage regulator box there.. but there's also a small black box with some wires going into it and a flat more modern looking fuse in it (plastic fuse casing looks a bit melted but the metal link looks ok inside), as well as another small black box which might be a relay??.. Very very novice here so these panel lights will have to sink down my TODO list for a while until I've learnt more.

Wipers

Moved on to wipers not working today. At the motor, I'm getting voltage on the green wire feed from the ignition when that's on but nothing on the other two (LGN, LGR) whether the switch is on or off. I would like to manually supply voltage to the motor on those three pins to check it directly with no other wiring in the circuit but I am not tooled up yet with spare wire and test leads so I can't do that at the moment. I removed the switch and measured resistance across all pairs of pins with the switch on and couldn't get anything other than infinite ohms so I am going to order a new switch. I don't completely understand the pin-out but I'm fairly sure with the switch on either two or all of the spades should be connected and show low ohms? Speaking of pin-outs, looking at the 2A wiring diagram I can see I have the right coloured wires going from the wiper switch with 4 spades to the input box on the wiper motor but if somebody removed the wires and asked me to use the wiring diagram to put them back on the right spades at the switch and wiper motor I couldn't do it. The switch and motor don't mark the spades in any way that would help me use the numbering shown on the wiring diagram. So I take photos before I touch anything.

The wiper switch I am replacing only has two positions, off or on. What is the purpose of the two LGN and LGR feeds over to the wiper motor? Does the wiper motor have two different speeds?

Doing some research it looks like S3 had two speed wipers and an extra (5th) wire over to the motor for that. It looks like the switch on my 2A is not so much "off/on", but "self-park/always on". So it always needs ignition feed on the green, then it will either a) power the wipers until they return to horizontal, or b) power them always, depending on if the switch is up or down. So if you turn them off mid-stroke they still return home. How's that sound? I've had this Landy 2 years but still haven't driven it! FIxing wiring helps if you know what it's MEANT to do.

A digital test meter will show battery voltage(ish) if just one strand of wire remains intact. You need a test bulb as well. Whilst the meter will show voltage it doesn't show that the wire is carrying sufficient current.
Case in point. My RRC fuel pump stopped working. Multimeter showed 12v at the connector. Connecting the pump directly to a battery ran it perfectly.
Bit of headscratching then connected a test bulb (sidelight bulb in a holder with a couple of wires connected) to the feed wire in the loom connector with the other bulb wire to a good earth. Nothing, not even a glimmer. Clipped a needle into the bulb wire & poked it through the insulation on the loom behind the connector. Nothing. Got back short distance from the connector & the bulb lit up. Stripped the wire & the last inch or so was badly corroded with few strands intact.

Can you provide a good link for the needle tool or probe fitting you used? I've been wondering how I might find a problem somewhere along a visibly unbroken length of wire..

There are loads around.
I have a Bosch kit (hand me down from dad)
But something like this
https://www.ebay.co.uk/p/Pair-of-In...er-Em03-New/1280838411?iid=181179386348&rt=nc

I prefer the clip ones as they stay on so releasing your hand and stays put. You may need some adaptors for you DMM leads though don’t know what you have.

J

scottonthefen said:

Can you provide a good link for the needle tool or probe fitting you used? I've been wondering how I might find a problem somewhere along a visibly unbroken length of wire..

Click to expand...

Home-made. Many years ago I had a Reliant Scimitar & as they are GRP much on those is earth-by-wire so chasing down electrical issues was a frequent job!
I just use an old car 12v bulb holder with a couple of lengths of electrical wire attached. Small crocodile clip on the end of each wire. Ordinary dress making type pin or sewing needle that I can push through the insulation & then clip the croc onto it.
I also have a short length of electrical wire with a pin soldered on the end that so the bare end can be gripped in the croc clip leaving me free to use the pin. (The latter can also be used with your multimeter, just clip the bare end to the mm wire)
In addition I have a couple of 12 foot lengths of electrical cable with a croc clip on each end. Handy for checking earths - just clip one end to the battery earth terminal.
Smear of silicone sealant over the wire after you've finished probing to seal any holes isn't a bad idea.

Your panel lights problem sounds like you have a relay connected into the circuit somewhere, but you'll have to investigate a bit more to know how that has been connected and what it does. Did a PO fit some extra lights maybe?
Your research on the Series 3 wiper motor is correct. The input to the park switch is the green wire, the output is the NLG wire. The input to the wiper motor is the RLG wire (assuming it's a single-speed motor). The wiper switch connects the RLG wire from the motor to either Green (On) or NLG (Off). To test the motor, connect wiper motor terminal 5 (RLG) to a live feed, but don't connect terminal 2 (NLG) to anything. The motor should run, but the wipers won't park. If that works then the next step is the wiper switch, but we'd need to know the switch details (model no) to know how to check it.

Spot on ExMil109, the panel lights switch had been wired to a relay on the bulkhead for some spot lights. I took them off about 2 years ago during the strip down and forgot about them.

As I want the panel lights switch to turn the panel lights on (call me old fashioned), and I didn't think much of the route or amount of wiring or where the relay was I just decided to take it out. While I was there I found a whole other switch I hadn't noticed before and an LED illuminated cigarette lighter - both let into the side of the instrument panel compartment below and to the left of the steering wheel. I traced the new switch to the other relay on the bulkhead and along the side of the chassis to what was a rear work light. Again, didn't like the wiring or the switch there or the relay position.. so took it all out. I'll take the LED lit cigarette lighter out when I get time too. Removed wiring in photo. I will probably fit spots and maybe a work light myself at some point but I'd rather have the switches on an extension panel and a neater relay and wiring arrangement.

Brake lights are working with the new switch and I've fit two new indicator fittings on the rear. Rear Right still only works 90% of the time and I still suspect the indicator stalk Right switch..

I put current straight into the wiper motor as suggested and in various other combinations but got nothing - and it did look knackered. I ordered a new motor and that's arrived. Father's Day tomorrow so I might even get chance to fit it.

Well, at least your PO used a relay. My Series LWB had various electrical bodges when I got it, mostly bits of black wire direct from the battery to various switches, plus some tinfoil in the fusebox! I always remove any non-standard wiring to start with, get everything working and then add back any extras I need, keeping a note of what is connected where for later reference.
Your indicator problem does sound like the switch. It's been ages since I worked on a Series 2 indicator switch, but I think you can dismantle it to check the innards. If you bypass the switch, does that make both indicators work?

I got time to fit the new wiper motor today. Most of that time was moving the gear and drive cord from the old motor to the new one but I got to test as you suggested before packing up and on giving it a live RLG I blew the ancient 35A A3-A4 fuse in the fusebox - which is a lot more than the old wiper motor managed. It looks a very very old fuse, perhaps the equivalent of a 15A by today's fuse ratings. And the wiper motor will be the biggest current the fuse has had through it in about 12 years of being stood up before I bought it and began the strip down so I don't think I did anything wrong just a very old fuse. We'll see I've ordered some more fuses and a couple of 15A inline circuit breakers which will behelpful if I have a repeating problem that takes a few attempts to find. Fingers crossed I'll pop a new fuse in and find the wiper motor works. I've ordered an SPDT switch that will allow me to pass either G and RLG or RLG and NLG and I know now I can measure the resistance across the switch pins with the switch on and off to work out which pins are connected for which switch position. Getting there with some help so cheers! (I'll try taking the indicator switch out the circuit when the wipers are working..)

tinfoil in the fusebox.. there's an idea while I wait for those fuses. (only joking!)