Charging light behaviour

[belfastguzzi]

The charging warning light (car - Land Rover) normally comes on when revs are very low and output drops. Today I've had peculiar opposite behaviour. The first thing was that the warning light lit when the ignition was turned off and even when the key was removed! Now that's not happening, but the strange thing is that the light stays off at low revs and then glows brighter as revs increase and stays lit while driving. What's happening?

[Paul Minnaert]

it's an english car, time to get rid of it.

[belfastguzzi]

it's an english car, time to get rid of it.

Twenty-one years done: another twenty-one to go!

[raz]

Twenty-one years done: another twenty-one to go!

Just get rid of the bulb then

[Dan M]

The charging warning light (car - Land Rover) normally comes on when revs are very low and output drops. Today I've had peculiar opposite behaviour. The first thing was that the warning light lit when the ignition was turned off and even when the key was removed! Now that's not happening, but the strange thing is that the light stays off at low revs and then glows brighter as revs increase and stays lit while driving. What's happening?

 

 

I'd say something is shorted internally. The regulator provides ground for the warning lamp circuit and opens the circuit (shutting off the light) when the unit starts working. If the light glows, there may be a faulty diode. Sometimes when the bearings fail there is contact inside the case shorting components. Any noises? What year / model? How many miles?

[belfastguzzi]

Dan, I was going to look for a short when I can get a chance, so thanks for that. It's 1987, but only 70,000 miles.

[gstallons]

The charging warning light (car - Land Rover) normally comes on when revs are very low and output drops. Today I've had peculiar opposite behaviour. The first thing was that the warning light lit when the ignition was turned off and even when the key was removed! Now that's not happening, but the strange thing is that the light stays off at low revs and then glows brighter as revs increase and stays lit while driving. What's happening?

 

With thr ignition "on", this charge light signifies a "difference in potential" either under/over charging. When you have proper charging taking place the light is out, when the vehicle is not properly charging the light is on. Your particular problem that is taking place could be a blown fuse, wiring problem, or alternator/regulator problem. the cheapest is to visually inspect the fuses, wiring ,etc.. If that is good, take the alternator to a rebuilder for testing and repairs. HTH!

gene

[Dan M]

It's 1987, but only 70,000 miles.

 

Famous last words...

 

Not wanting to send you on a wild goose chase (so to speak). I looked for a wiring diagram for this unit but unfortunately my Land Rover / Lucas info from the 80s is spotty at best. I did discover that it uses a "warning lamp control unit" that can effect brightness of the warning lamps. It doesn't seem likely that there is trouble with that if only the charging lamp is acting up. The fact that the lamp comes & goes and changes in brightness would indicate either a loose / corroded connection or an internal problem with the alternator. If it were a blown fuse the trouble would at least be constant. - good luck.

[BRENTTODD]

Replace regulator there cheap see what happens. My money is the light goes out. As soon as the light goes out the for sale sign goes on. Then you can by a VW they never have any electrical problems HA HA

 

Good luck best wishes

Brent

ps take your time it will show it beady eyes they always do

[mike wilson]

Is the rectifier/regulator part of the alternator? They often are, these days. If so, comparatively easy and cheap to change for a fresh one. Worked for me.

[Garsdad]

Throw a meter on it and see what it is doing. Charging normally, look for an issue in the indicator circuit. Not charging properly? Look at the regulator or alternator.

 

I was on the third alternator in 52,000 miles in the Ford Fucus when I traded it in... they do crap out sometimes. They are not cheap- they ran $186 just for the part!

[belfastguzzi]

Thanks to all for helpful advice on non-Guzzi matter. I'll start at the last post and work back – put a meter on it and see what's coming out of the alternator. There was some welding done on the chassis a week or two ago, but I disconnected the battery and unplugged the alternator – so that shouldn't have affected anything...?

[belfastguzzi]

Voltage measured at the battery is rising from around 14.2V at idle to the high 15s - 16V on the road.

A sustained 16V is too high?

[Dan M]

Voltage measured at the battery is rising from around 14.2V at idle to the high 15s - 16V on the road.

A sustained 16V is too high?

 

Yes, you will boil your battery. The alternator is overcharging. If there is a poor connection and the regulator is sensing less voltage than is actually present, it will up the voltage until it is satisfied. Typical charging voltage (above idle) is 14.5. It is possible, but unlikely that the regulator is bad. Since you had the alternator and battery disconnected for the welding I'd go back and look closely at all of those connections. Make sure nothing was left off or loose. Look for corrosion at the terminals.

[BRENTTODD]

Dan is right also check that the alternator is not puting out a/c voltage that will give you a heap of trouble. Make sure those grounds are good and tight.

 

Brent