Strange electrical happenings....

[Nick Farrow]

Hi all,

My new purchase (Series 3 GT) is causing a few headaches due to some electrical issues. When I bought it, the ignition light was on all the time (one reason why I got the car cheaper), and I have recently replaced both the dynamo and the dynamo regulator. This seemed to have solved the problem....there is a but! I took the car for a ten mile run last night but after about 8 miles it blew the 'ignition on' fuse (indicators, gauges etc) and shortly afterwards the ignition light came on again. I changed the fuse this morning and all seemed well - the ignition light was off and everything seemed to be working....but after a short test drive, the ignition light came on again, but it was getting dimmer as engine speed increased (but never going out). I've also noticed that all the guages show higher readings as the engine speed increases (the temp guage scared the crap out of me at one point, but I knew it wasn't overheating as the oil pressure was still good). Also, the ammeter seems to be showing a positive reading all the time - I thought that it should mainly stay at zero or a tiny bit positive/negative depending on engine speed and electrical load.

Has anyone got any ideas what might be happening as electrical stuff goes way over my head!

Cheers

Nick

 

[MikeH]

I would check the regulator. Does it use a generator or an alteranator? I remember a Ford Falcon I had with a generator. As I recall there were some steps I had to go through to correctly polarize the regulator. Does the Alpine use a volage regulator for the gauges? If it does I would check that too.

 

[sunalp]

Nick, having just gone through a similar situation with my S4, make sure your grounds are good and clean. A bad ground will cause all sorts of weird problems. For instance when I turned on the lights the high beam indicator was on all the time and the directional light didn't work at all. Also the dash light wouldn't work either.

Get a good wiring diagram as well. You never know what the DPO has done with the wiring. When I got mt S3GT, it had three different horns hooked up, and none of them worked!
Cheers!
Steve

 

[Jim E]

After paint my S3 was possed by electrical demons, spent hours tracing the wires and all was right. In the end it hit me was ground issue so added a ground to each tail light and everything worked fine, You want to make sure the ground on the trans to the frame is good and there. I also sugest you dump the generator if that is what you are running and switch to an alternator

 

[Tom H]

It sounds to me like the regulator is not working correctly and allowing the generator to put out TOO MUCH charge. This would explain the over- reading gauges, and the constant + ammeter. As other have noted this could be due to loose connections including ground conections . Check especially around the Generator and regulator circuits.

If you can get a voltmeter to check things it would be a big help. Measure the Voltage at the battery while the motor is revving a bit - say 1500- 2000 RPM. The voltage should be about 14.5 volts . If over 15 V you are definitely overcharging.

Tom

 

[Nick Farrow]

Cheers for the input....I will check those things...BUT I may have found at least some of the problem! I had a good look under the dash today at the wiring and it's been pretty badly butchered! The instrument backlights don't work becauase they're not connected, there's all sorts of odd wires and 90% of them are red....not easy to trace stuff! The ammeter has been connected to the ignition switch, so lord only knows what it's reading! It all looks a real mess under there! I'm thinking about replacing the entire loom!

BTW how many ground connections are there?

 

[sunbeammadd]

Sounds very similar to the problems I had on mine for quite a few years. Nothing I tried ever made a difference and in the end gave up and fitted an alternator and replaced the fuse box with a modern blade type. It may not be original but at least now it all works as it should!

 

[Nick Farrow]

If you can get a voltmeter to check things it would be a big help. Measure the Voltage at the battery while the motor is revving a bit - say 1500- 2000 RPM. The voltage should be about 14.5 volts . If over 15 V you are definitely overcharging.

Tom

OK, did a voltage check and the battery voltage ranges from just under 12 at idle upto about 14.5 at 3000rpm. That bit at least sounds good.

Am I right in thinking the ammeter should be wired in series with the Solenoid and control box?

 

[Tom H]

Yes, The ammeter should be wired between the solenoid and the A terminal of the control box. The A termnal is the same terminal that has the Brown wire that goes to the fuse box. All this is based on the schematic I have downloaded from someone's post.

And yes, your Voltmeter reading sound OK.
Tom

 

[Nick Farrow]

Yes, The ammeter should be wired between the solenoid and the A terminal of the control box. The A termnal is the same terminal that has the Brown wire that goes to the fuse box. All this is based on the schematic I have downloaded from someone's post.

Tom

That's what I thought; I too have a schematic which I've been using. I don't think my car came from the factory with an ammeter as the brown wire from the solenoid goes directly to the regulator and the spade connector it has is shared by the wire that goes to the fusebox. I'm guessing someone found an ammeter and decided to fit it but had no idea what to attach it to, thus connecting it wrongly!

 

[Nick Farrow]

OK....I've just noticed a couple of things. When the lights are on and the ignition is turned on, the fuel gauge turns itself off (and possibly so does the temp. gauge, but the engine wasn't warm so couldn't see). Also, when you rev the engine with the lights on they have a tendancy to flicker somewhat. Very odd stuff... anyone got any ideas what's going on?

 

[V_Mad]

Sounds like a faulty regulator box. The flickering is the regulator cutting out. I wonder where did you get the regulator box from, was is reconditoned or second hand?

 

[Tom H]

The flickering sounds like a faulty regulator, although a old style mechanical regulator like on these cars may have anormal amount of fliicker. After all they operate by switching ON and OFF rapidly.

But I think the other problem, with the gauges, is faulty wiring. You say with the motor running and the lights ON the fuel gauge goes to zero. With the motor still running , I asume if you turn the lights off the gauge goes back to normal? Is that quite repeatable? And what if you turn the lights ON but turn the Panel lights OFF, I think you can turn the OFF with the Panel switch on a SIII, right? If so does just turning the Panel lights ON and Off have the same effect on the gauge- it goes off and on

Tom

 

[Nick Farrow]

The flickering sounds like a faulty regulator, although a old style mechanical regulator like on these cars may have anormal amount of fliicker. After all they operate by switching ON and OFF rapidly.

But I think the other problem, with the gauges, is faulty wiring. You say with the motor running and the lights ON the fuel gauge goes to zero. With the motor still running , I asume if you turn the lights off the gauge goes back to normal? Is that quite repeatable? And what if you turn the lights ON but turn the Panel lights OFF, I think you can turn the OFF with the Panel switch on a SIII, right? If so does just turning the Panel lights ON and Off have the same effect on the gauge- it goes off and on

Tom

If the ignition is on (whether the engine is running or not) and the lights are then turned on, the fuel gauge will drop to zero. I had a similar idea about the panel lights, but they are not really connected (there's only one wire attached to the switch) and they don't work. It's very repeatable...happens every time you do it!

Sounds like a faulty regulator box. The flickering is the regulator cutting out. I wonder where did you get the regulator box from, was is reconditoned or second hand?

The box came from Speedy Spares. It looks brand new. It seems to be charging OK and isn't putting out too much voltage.

TBH I think all the under-dash wiring needs replacing...it seems to be a real mess.

I did try to get the dash panel off the other day to get a better look at what's going on but I couldn't get it past the steering column cowl. The top half just didn't seem to want to come off...is there something apart from the two screws holding it on?

 

[Tom H]

You say the panel lights are not connected. But then you say there is only "one wire attached to the [Panel] switch". I am guessing that the lamp holders are still plugged into the gauge cases. And that the lamps may still be wired , just not wired to the Panel switch. If so, pull the lamp holder out of the back of the gauge case(es) and see if the condition goes away. I suspect some interaction betweeen the gauge lighting circuit and the gauges. There should not be any interaction, they are separate circuits, but if someone has messed it all up, who knows what is connected to what. And I'm not so sure a new harness will help. If the old harness is OK, then it just needs to be connected correctly. But a new harness is no easier to connect up correctly than an old one.

Tom

 

[Nick Farrow]

I'll remove the lamp holder(s) from the back of the gauge(s) when I get home from work this evening and see what happens! I wouldn't replace the entire harness anyway as the lights, wipers, indicators etc seem OK; I just think the instruments need to be re-wired as everything seems to be wired up incorrectly. Whoever wired it all up decided to wire much of it using red wire, so it's very difficult to see what's going on!

Any tips for removing the top half of the steering column cowl?

 

[V_Mad]

............the steering column cowl. The top half just didn't seem to want to come off...is there something apart from the two screws holding it on?

Nick, there are three screws holding the cowls together so remove all of them and it should come off easily.

Removing the dash is the way to go so you can tidy up all the wiring, but the heater control cables, choke cable and speedo cable all need to be released to do this. NB Disconnect the battery first!

As you have an early car, consider renewing the wiring harness. If its the original, it will be well beyond its best by now. If not, check/repair/test all terminals while the dash is out otherwise you will have to work upside down later

Behind the dash I would recommend wiring all the earths together, and having a connection to chassis at each end to make it reliable. That way if you lose one, it will all still work. Make sure you fully test all the wiring before fitting the dash back, especially the main beam and indicator warning lamps as they are a pig to access afterwards.

That is one beautiful car Nick, why not treat us all to a bigger picture?

 

[Nick Farrow]

Thanks Chris. I couldn't find a third screw for the top half (bottom half came off easy enough), but I had been hanging upside-down for about 2 hours at the time and was getting a little impatient....I'll have a better look when I get home!

Here's a couple of bigger pics of the 'beast'

 

[Nickodell]

That is one luscious beast.

 

[Nick Farrow]

Quick update. Removed the dash last night. After stripping out most of the extraneous red wiring and a little bit of cutting back of the insulation I managed to locate much of the original loom and traced where everything was going. I've labelled it all up and it's just about ready for re-installation.

There were a couple of interesting things I found: The supply for the panel switch from the head light switch was connected to the fuel gauge (thus why the fuel gauge was going down to zero when the lights were turned on!!) and the other terminal on the fuel gauge was connected to the voltage stabilizer (as it should be), but there was no connection to the fuel tank sender! The sender wire was connected to the voltage stabilizer. The ammeter was connected through the ignition switch (nice!) and the heater was connected with a wire shoved in behind a spade connecter.

It was all a bit of a mess really, but I'm hoping when it all goes back together it should perform a lot better....stay tuned!