No charging, no rev counter, two unidentified wires...pics..

[berni29]

Hi

I am useless at electrics. I have just got the plus 2, it does not charge, but had a new alternator back in 1992, and has done few miles since then. Also rev counter does not work. No electronic ignition. There are two wires without homes. A green one near the fuses, and a blue and white one near the coil (comes out of the same place as two beige ones which go to the coil). The alternator wires going to the back of the alternator carry 0.6v with the ignition on. The green wire varies between 5v and 12 in a cycle. There is no magnetic field with the alternator spinning and reving the engine produces no change in volts at the battery. Picture link below.

http://www.searchsmart.co.uk/wire/


Any help appreciated!! The front of the car has been rewired.

[types26/36]

Bernie,
According to the Lucas wiring colour guide a green wire is "accessories fused via ign switch" its a little hard to see if your green wire has an other colour trace.
A blue wire with a white trace is "lighting switch (head) to dipper switch"
Ofcourse it may not have been wired according to the standard Lucas system.
I can send you the wiring guide as an attachment as the web address no longer seems to work, you would have to supply your email address.
Brian.

[john.p.clegg]

Charging:-the first question is-Does the ign light illuminate with ignition on,Does it extinguish with engine revs?
John

[berni29]

Hi There

The ignition light is on all the time, no difference with engine revs, and the ammeter shows discharge at all times. The green wire near the fusebox has no trace colour, and can reach the relay on the left or either fuse box, and the blue (white or light colour trace) wire near the coil seems to only have one possibility which is on the coil. I'm a bit reluctant to just plug it in. Could it have something to do with the rev counter, or unlikely?

All the best.....

[john.p.clegg]

Charging II,if the ign light goes out (with the ignition on)when you pull the connector off the alternator it means that a supply is getting to your alternator but it is not producing any output......you could try looking at the brushes,maybe clean the commutator with fine emery paper(two copper coloured circles where the brushes contact........other than that ,thirteen years is not all that bad.....

John

[carrierdave]

Hi Berni,
You have the same 3 block fuse carrier arrangement as my car. There should have originally been 2 feeds to the back of the original dynamo, one large brown cable and one smaller green/brown cable ? From the photo it would appear that the green you are looking at is for the temperature transmitter on the end of the thermostat housing ? well that?s the colour of mine ? It come out of the harness right near the end of the fuse boxes.
As for the Blue/white trace colour wire can you be more specific as to where it comes from. I have looked at my car and there are two cable that come from the wiring loom just below the end cab, right in line with the distributor ? One is for the oil pressure pick up and the other goes to the + side of the ignition coil.

I also found this that may be of some assistance:
1. Wire at E from control box, this is an earth and can be discarded.
2. Wire at D from control box to alternator, no longer required, wire can be removed or insulated at both ends if you do not want to disturb wiring harness.
3. Wire at WL goes to ignition switch through warning lamp, remove connector from control box and join this to the F wire
4. Wire at F join to WL at the control box end, and to the 'IND' terminal on alternator at other end.
5. Two wires at B on control box, disconnect and join together.
6. A new piece of insulated cable is required to join the main positive alternator terminal to the battery side of the solenoid, the grade of the wire required is 80/0.012" (or metric 80/0.3mm) rated 40 amps, that means a cable with 80 strands and each strand is 0.012" diameter.
7. The third terminal on the alternator terminal is for battery sensing also to the battery side of the solenoid. Not all alternators have/need them, apparently the modern alternators are now self sensing.

For a picture go to http://www.mgcars.org.uk/carclub/technical-7.htm

Hope this is of assistance - Please send me more data on the Blue and white cable.

Thanks

Dave

[berni29]

Hi...

When I pull the connector on the alternator off the ignition light goes out, so I guess that the alternator is faulty. I have an old one, so will try that.

Many thanks for all the help......

Berni