[Bettsbooks]

Our MK VI is giving us fits with the generator not showing a charge. We had it rebuilt for positive ground with new brushes and bearings, and it bench tests fine. Installed in the car, it does not shut the red light out (new voltage regulator) nor show a charge on the amp meter. We have tried to polarize it several times, but can not get a spark from the negative terminal of the battery. We accidentally touched the positive terminal and it sparked. we have done the tests that the service manual calls for to no avail. We thought the RD 4395 condenser might have failed but can not find a replacement for it from IntroCar or Flying Spare. Can anyone suggest places to look for the fault, and /or to supply a new condense? Thanks.

 

[mikebentleyturbo2]

There is no + or - connections on a dynamo ? Do you mean Field and output?
A condenser is nothing to do with any generator circuit I've ever seen?
Mike

 

[Jeff R 1]

Did you have it rewound as well, the field and/or the armature ?
The condenser is just to keep the radio quiet.
Try it with out the condenser, maybe it's shorted.
You don't rebuild it for positive ground, it's wound correctly or it won't work.

Where did you get the new regulator from _ maybe faulty ?

 

[Bettsbooks]

Hi Mike,
The condenser is really a noise suppressor for the radio, but it is referred to in the Service Manual as a potential cause of the generator not charging. I have no idea why.

 

[Wraithman]

If the condenser is shorted, it will wreak havoc on the system. Leave it off for now.

 

[Bettsbooks]

Hi Jeff,
The Regulator came from IntroCar. The generator bench tests fine, so we have an electrical issue somewhere. The fuel gauge reads full all the time but the green light is always on. The sending unit is new, also from IntroCar. I reversed the wires yesterday but it made no difference. So there is a fault somewhere in our wiring.

 

[Bettsbooks]

We disconnected it yesterday and have left it that way, but nothing has changed as far as these two problems. We don’t have the radio hooked up so not having it connected is not an issue at this time.

 

[Jeff R 1]

If disconnecting the condenser does nothing to improve the situation, then you have at least ruled that out, but since you don't have a radio, just omit it.
This sort of thing is almost impossible to trouble shoot on a forum, mainly from lack of info, and what was changed to try and get it to work.
The fuel gauge problem may be just another issue apart from the generator issue.
It's a logic procedure of elimination to isolate what's wrong.
Disconnect the fuel gauge circuit from it's 12 volt source and see if that cures the problem.
Leave it disconnected for now until you can get the generator circuit working.

Has this problem developed just recently or has it always been this way, it's not quite clear ?

Take a multi meter (hopefully you have an analog one) and check for the wires continuity to the field.
That's the thinner wire from the generator to the regulator.
The regulator should be marked "F" for FIELD on the lid.
When checking, disconnect the wire at one end.

We'll start with something simple.

If you don't have a multi meter, get one, and learn how to use it, you must have one to sort this out.
Just guessing and hoping it will fix itself, very rarely works.

Do you have a manual with a proper wiring diagram, the one available on line has not been scanned properly ?

 

[Bettsbooks]

Hi Jeff,
This car has been off the road for 20 years, and we are just getting it going.
We do have continuity from the generator to the Field connection on the Regulator. We have the Owners Manual wiring diagram which seems better than the one in the Service Manual. I’m beginning to think we will need to pull the dash apart next to see is if a wire or two has been dislodged. It’s got to be something simple, or at least we hope it is!

Moderator note: Please note that there is no need to quote a previous post when you are replying if you are following the train of thought in the thread.

 

[Jeff R 1]

Where has it been sitting, if it's been sitting somewhere damp and humid, then check the fuses for oxidization, and in the junction box beside the fuse box.
Also the connections in the fuse box itself.
Could be a bad earth from the regulator too, do a visual check here, not a continuity check.

I can't remember if there is a fuse for the dynamo or not _ easy enough to check.

When removing the centre wood facia to get at the dash, turn the two screws underneath, clock-wise to release the tabs.
There are also 3 screws at the top/front, just out of site.
Use a bit of cigarette cardboard to protect the wood from the tabs when sliding the facia out from the bottom.

You will also have to unscrew the speedo cable to allow the gauge panel to come forward.
Be sure and have the battery disconnected.
Be careful of the temp gauge mercury connection tube.