I need help

I took my car on a bit of a run Liverpool to Lancaster and came back in the dark the problem is as I drove along the lights were on main beam and would go bright then dim all on there own and would stay dim then brighten up

Any Ideas!!!!!!

What car is it?

is that bright and dim in relation to engine speed?

Alternator belt loose?

Id patent the concept if I were you!

In responce to the above

1600 xflow westfield

it seemed to happen all the time flat out or slow!

If there is no pattern it could be a bad earth that gets better or worse depending on vibration.

Could be the voltage regulator on the alternator.

Were the dash lights going dim / bright as well?

Stu

The standard Xflo alternator is a Lucas ACR type which have old the standard 3 spade block connector, as these are carry a high current and are exposed to excessive vibration hence are very prone to arcing, which causes big problems for the alternators solid state voltage regulator.

Clean the spades (either remove the rear cover for acess or use a nail board) and also crimp the connectors slightly so they make better contact.

Apart from that as already suggested clean and check all main earth abd batter connections, and fan bely.

Also do quick check on the charging voltage on and off load at 2000 to 3000 rpm

[Edited on 3/4/07 by britishtrident]

Second the above - I suspect when you remove the plug from the alternator it will be blackened & cooked - the reg might have survived but might not. if the plugs not cooked & the belts tight then sounds like a dodgy reg.

I had a similar problem on a Xflow when I didn't use a nylock to "secure" the alternator (I used the stupid "self-gripping" flanged nut provided by Halfrauds).... Bag of pants.... Alternator ended up being attached by one bolt when the other one fell off..... Instant loss of belt tension and hence alternator drive....

Luckily a very friendly bloke drove past (this was in deepest darkest Northern Ireland), stopped and went 3 miles to have a rummage in his garage and found a motorbike head stud and four nuts to go with it which I was able to temporarily re-attach it until I got the local B+Q 25 miles away.... Top geezer!!!!

My guess, Bad earth

Hi whitestu yes the dash lights were doing the same dimming and then going bright!

Thanks to everyone for all your advice it looks like I know what I am doing this weekend

Had a Lucas alternator on a mini do exactly this, and the lights were getting very bright indeed. Turned out to be a dead voltage regulator, but was cheaper to get a recon alternator.