red light on.

jd · Post by jd » Tue Jan 11, 2005 9:08 pm

whats it telling me?

checked the fan belt which was loose,sorted that but its still on.

alternator?

69Olive · Post by **69Olive** » Tue Jan 11, 2005 9:36 pm

My alternator light has been on red since I bought my car just over a year ago, but I haven't had a problem.

The batteries charge fine and I have never had a problem starting. I have a feeling it's the regulator. I'm planning to take it somewhere where I can swap the part over temporarily to confirm this before shelling out for a new one. I've been to busy fixing other things but I must get round to this.

I have been advised to check the regulator first before ripping the alternator apart.

bjmullan · Post by **bjmullan** » Tue Jan 11, 2005 11:23 pm

I had the same problem a couple of months back. Took the alternator out (which is an easy job) has it checked and it was okay. Put it all back together again cleaned the connection and check all the wiring to the regulator and it was fine, no more red light.

To see if you have a charge you could put a meter across your battery when the engine is started (above idle) and see if it's greater than when the engine is stopped.

Barry · Post by **Barry** » Mon Jan 17, 2005 7:50 pm

Bredan's right, put meter on, get reading (hopefully over between 12 - 12.8 if your battery is charged), start car, you're then after something beginning 14 - 14.5, 14.8v fine, much more and it's probably regulator / control unit, much less then above plus alternator. You probably won't have any more than the standing volts though, if the lights staying on (if the running voltage is good then it must be something in the charging light circuit). Don't forget you need a decent battery on the car to power up the alternator (its only disadvantage to a dynamo- you can't charge a very flat battery with an alternator). Obviously if your battery is starting the car, that'll be plenty of juice for charging though.

Then its down to history: if the car has been standing then my money would be on sticky brushes in the alternator (my light came up after the car was re-built, but suddenly went out after 5 miles or so therefore prob. was sticky brushes).

If you've done some welding, then suspect alternator diode pack. If you've received a jump start (or given one) then poss. diode pack or regulator. You would have to be mega-unlucky if you've done the above and done damage though.

Also check all cables and earths (including fusebox end: the alternator requires battery voltage to power up the electro-magnetic field: (I believe this is actually how the regulator fluctuates the alternator power, it simply changes the feed TO the alternator electro magnets, therefore varying the power output). On mine there is an earth strap at the rear (pointing forward in the car) of the alternator that I thought looked a bit fragile, so I sistered it up with a second one.

After that its going to be a case of either borrowing units to try, or send your bits for testing.

Bob_Salmon · Post by **Bob_Salmon** » Mon Jan 17, 2005 8:23 pm

Barry wrote: After that its going to be a case of either borrowing units to try, or send your bits for testing.

Sounds bloody painful

Bob

Barry · Post by **Barry** » Mon Jan 17, 2005 8:27 pm

Just cross your legs and think of England ....

roger · Post by **roger** » Mon Jan 17, 2005 10:13 pm

Why do you want to think of me.....?

Roger England

Barry · Post by **Barry** » Tue Jan 18, 2005 11:15 pm

Not THAT England (although !'m sure you're very lovely).

jd · Post by jd » Thu Jan 27, 2005 10:11 am

Barry wrote:Bredan's right, put meter on, get reading (hopefully over between 12 - 12.8 if your battery is charged), start car, you're then after something beginning 14 - 14.5, 14.8v fine, much more and it's probably regulator / control unit, much less then above plus alternator. You probably won't have any more than the standing volts though, if the lights staying on (if the running voltage is good then it must be something in the charging light circuit). Don't forget you need a decent battery on the car to power up the alternator (its only disadvantage to a dynamo- you can't charge a very flat battery with an alternator). Obviously if your battery is starting the car, that'll be plenty of juice for charging though.

Also check all cables and earths (including fusebox end: the alternator requires battery voltage to power up the electro-magnetic field: (I believe this is actually how the regulator fluctuates the alternator power, it simply changes the feed TO the alternator electro magnets, therefore varying the power output). On mine there is an earth strap at the rear (pointing forward in the car) of the alternator that I thought looked a bit fragile, so I sistered it up with a second one.

thank you barry

Barry · Post by **Barry** » Thu Jan 27, 2005 1:28 pm

No Probs, let us know how you get on.

jd · Post by jd » Sat Feb 19, 2005 2:19 pm

Barry wrote:No Probs, let us know how you get on.

it was the regulator,thanks again

Barry · Post by **Barry** » Sat Feb 19, 2005 8:12 pm

Well done, how did you diagnose it in the end? (Useful for the future ...).