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MG Midget and Sprite Technical - Dodgy electrics - where do I start?

My drive home from Silverstone in the gloaming last night brought to the fore my issues with dubious electrics. These manifest as very slow indicator blinking when the headlights are on (they're fine when lights are off). At low revs they effectively don't blink, with revs they eventually do but there are many seconds between blinks.

I also think the headlights (and main beams) look rather dim and yellowish - they are sealed beam halogens I believe (how to check?).

And lastly the wipers are also glacial in their sweep speed.

Now these may be related or all separate issues - I don't know.

Given that mine is an all-plastic-bodied IOW frog with a fairly fresh looking alternator how might I go about trouble shooting these problems? I have a multimeter.

Thanks for any advice...
Jordan Gibson

You could check the volts drop across the loom, e.g.

- battery +ve terminal to brown on fuse-box
- brown on fuse-box to head-light connector (with headlight on)

Anything more than 100mV (0.1V) is poor.

General advice would be:

- ensure clean battery connections
- rebuild/clean posts/connectors on the solenoid
- ensure clean earth-cable to body connection (on bulk-head)
- check good earth for headlights (black wire)

Some of this might help your wiper motor; but also grease or WD-40 the wheel-houses behind the dash.

A
Anthony Cutler

In my experience all this sounds pretty normal!
Simon Taylor

Are you running the halogens just on the old circuit, or did you install relays?

Check the alternator is a good one, it's not unknown for the new ones not to be any good!

Check all the connections in the wiper motor as has already been mentioned
rachmacb

First thing I would do is check battery voltage without engine running and then with engine running.
Dave O'Neill 2

Simon
Get it fixed this is not normal!

Jordan
Follow Antony's advice those are the basics and need to be good before you do anything else
And ditch the sealed beams they are crap. And giving lights a direct feed from the battery through a relay is a good idea even with normal bulbs
Onno Könemann

Thanks all - will do as you say and see where are then.

Oh and the car was fitted with halogens from 'new' according to the spec on the invoice - not sure about relays.
Jordan Gibson

This sort of issue usually comes down to earthing, as I understand it. I was having similar problems once, and when cleaning my battery post clamps I found that the positive cable was corroded for a good couple of inches under the insulation near the clamp. Granted, that was on the positive side and not the grounded side, but the same advice applies. I'd check all connections first and make sure they are all very clean, and perhaps protected by a dielectric grease or something. If you still have problems, then look at the battery. I like to try the cheapest fix first. :-)

Interesting to hear you're having this problem on an IoW Frog. With all the earths being wired vs. screwed to the body shell, you might have a better chance of finding the culprit.

Cheers,

-:G:-
Gryf Ketcherside

Hi Jordan,

I solved all my electrical problems by finding a good auto electrician with experience of classic cars. Best £100 I've ever spent!
Andrew
aj robinson

I think Grif may have it nailed especially as it's got lots of fibreglass.
Poor earthing can cause the symptoms you've described.
The wiper motor may need different attention as Anthony has described. The grease in my wiper motor and wiper spindles was rock solid and was doing very lubricating! Amazing what a good clean and fresh grease achieved.
Jeremy
Jeremy 3

EARTHS.......!

Jordan, find and clean all the earthing points on the car, then follow on with replacing all the Lucar connector blocks.
Durite make them, P/N 0-004-71 for the singles and 0-004062 for the doubles.

Good luck,

Mark.
M T Boldry

This thread was discussed between 25/07/2011 and 10/08/2011

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