Control box and starting problem

[johner]

Hi,

I have my first electrical problem on my newly acquired mini. I drove it home last week, started it several times on the way home and it started and ran well. After sitting at my house for a coupe of days, it now won't start. The ignition light doesn't come on when I turn the key and the car doesn't turn over on the switch. It turns over no problem with the solenoid button. I think I tracked the problem to a low voltage at terminal A1 on the control box. I've confirmed I have 12V at terminal A, but only see 0.2V at terminal A1 and at the brown/blue wire going to the ignition switch. I believe I should see 12V at terminal A1; can someone confirm? Is there an internal failure of the control box that could cause this, or should I be looking elsewhere?

Thanks

John

[floormanager]

Hi John,
Yes, A1 should be 12V. I tried for a long time to get a control box to work without success. I had too much voltage and lights going bright and dim as I drove along. Whatever you do, do not buy a cheap replacement - they are rubbish. In the end, I bought an electronic control module and fitted it inside the control box. Never looked back.

http://dynamoregulator.com/products.html

[Peter Laidler]

+1 to Floormanager. Just done the same to friends mini. New cheapo crap repro control box lasted just over a year - and out of warranty. Fitted internal ECM and now perfect.

But, there's an over-rider here. Just be warned that the ECM can fail instantly and without warning.

[johner]

Hi,

Thanks for the replies, that helps me with my troubleshooting. I've read that bridging A and A1 might be a temporary fix to get the car started, but wonder if that can potentially cause other problems. I need to get the car running so it can have a provincial safety inspection, so I'm tempted to do that whilst I sort out the problem and source a replacement.

John

[Ronnie]

Hi,

Thanks for the replies, that helps me with my troubleshooting. I've read that bridging A and A1 might be a temporary fix to get the car started, but wonder if that can potentially cause other problems. I need to get the car running so it can have a provincial safety inspection, so I'm tempted to do that whilst I sort out the problem and source a replacement.

John

This may help. > https://mk1-forum.net/viewtopic.php?f=7 ... 2&start=10

[johner]

Thanks for the offer Ronnie! I'm in Canada so might see if there's a local option first, then get in touch

Just as a follow up, I did a bit more testing today and verified it's a control box issue.I will remove the control box tomorrow to see if it's repairable, but I'm pretty convinced it's done for. I guess the problem may be a bad connection or break in the voltage regulator coil and I'm not sure if running the car with terminals A and A1 connected in this condition could cause a problem. The Lucas literature describes a test with the terminals A and A1 disconnected from the control box and connected together though so maybe this is ok? If anyone can chime in on this that would be a great help.

John

[AndyPen]

Hi John,

not directly answering your question sorry, but you may wish to keep the actual box if it has the correct date for your car on the base? Another reason for an ECM approach perhaps?

[Peter Laidler]

I think that all you can do to your duff control box is to clean the points by sliding a bit of medium emery across them. And if you are really game, with an accurate multimeter, you could try to re-set it as per the not so clearly written workshop manual.

But I wouldn't leave the tabs connected as you have said. You're simply going to create two problems out of one by current overload! Mind you, if you put a new wotsit/unit into the original box that's the problem solved

[johner]

The problem was pretty obvious once I got the control box removed (broken internal contact). I have temporarily bridged across with some 10 gauge auto wire and the car starts and runs again, so I'll be able to get my car in for provincial safety inspection and hopefully registered and on the road by the weekend. I''ll need to get a replacement and am leaning towards the solid state version. Thanks for all the help

John

[Peter Laidler]

VERY astute bit of fault finding John. Makes you wonder what caused that. Certainly not car dynamo voltages I'd say!

['S'-type]

An alternative approach (no pun intended) is to convert to an alternator set up whereby you keep the original confrol box but adapt the wiring. It looks pretty neat and original with the advantages of better charging. You have go ignore the elephant in the engine bay however, the alternator itself!
It's been done many times and is as follows:

Parts needed:
bracket 12G1053
pulley 12G1054
fan C37222A
belt GCB10825
1. Disconnect battery
2. Remove regulator box from car, carefully marking all connections.
3. Remove dynamo, etc.
4. Fit alternator, new bracket, and new belt.
5. Dismantle regulator (use junk regulator if you have one). Remove coils and contacts. Remove connections to blade terminals.
6. Solder links between terminals A, A1, and D, connecting all three.
7. Solder a link between terminals F and E.
8. Reconnect loom to correct terminals-EXCEPT-connect ignition warning light (brown/yellow) to terminal E.
9. Connect alternator to loom: Large wire to large terminal (output), and small wire to small terminal (sensing).
10. Reconnect battery

It's covered by Keith Calver here.

https://www.calverst.com/technical-info ... lternator/

[floormanager]

FYI, just built a spare ECM regulator, as I've had the original 10 years. Mounted underneath the regulator, using some old scraps of steel I had lying around. Not very pretty but it's all hidden away.

IMG_7452.jpg

IMG_7453.jpg

IMG_7454.jpg

I've got to fit, longer, countersunk screws, to sandwich it all together before fitting to the car.