Alternator woes?
Discussion
Right then chaps, need a bit of help please! My daily shed, an astra 1.7td mk3 with the vauxhall engine is playing up.
Thursday night my alternator belt snapped. Unfortunatly, I was staying in a hotel 140 miles from home, so had to get it sorted asap. I drove the car on battery power back to my hotel from work, about 2 miles, and arranged to get it fixed the next morning, ready to collect at lunchtime. Drove to the garage Friday morning on battery power again, no problems. Obviously the dash warning light was on constantly due to no charge going to the battery.
Picked the car up Friday lunchtime, all fixed, £38, bargin! Started the 140 mile drive home, all seemed well. About 15 miles from home, I noticed the airbag warning light on, which seemed odd, as I have never had a problem with it before, and the temp gauge was showing cold... I then realised that my dash was dim, so turned my headlights off and everything went back to normal.
Diagnosis on the move was no charge to the battery, and after getting home, u turned the engine off, and of course the battery hadn't got the power to restart the engine. The odd thing is the battery/ charge red warning light had not illuminated during any stage of this.
Now, when I turn the ignition on, I don't get the warning light on at all, static or with the engine running?
The other thing I noticed is, where the garage replaced the belt, they have left the earthing strap touching the fan wheel, which I only spotted tonight arcing out, due to it being dark! Using a mulitmeter, there is no charge going to the battery.
So... Does the dash warning light form part of the charging circuit? Ie if the bulb is gone, will it stop the alternator working? Sounds daft but I know on some older cars this is the case!
Secondly, would the earth strap arcing on the fan/casing damage the diode pack or cause the dash light to blow?
I'm 99% sure the main alternator is working fine, but I am concerned that the earth issue might have damaged somthing else within the system?
Thursday night my alternator belt snapped. Unfortunatly, I was staying in a hotel 140 miles from home, so had to get it sorted asap. I drove the car on battery power back to my hotel from work, about 2 miles, and arranged to get it fixed the next morning, ready to collect at lunchtime. Drove to the garage Friday morning on battery power again, no problems. Obviously the dash warning light was on constantly due to no charge going to the battery.
Picked the car up Friday lunchtime, all fixed, £38, bargin! Started the 140 mile drive home, all seemed well. About 15 miles from home, I noticed the airbag warning light on, which seemed odd, as I have never had a problem with it before, and the temp gauge was showing cold... I then realised that my dash was dim, so turned my headlights off and everything went back to normal.
Diagnosis on the move was no charge to the battery, and after getting home, u turned the engine off, and of course the battery hadn't got the power to restart the engine. The odd thing is the battery/ charge red warning light had not illuminated during any stage of this.
Now, when I turn the ignition on, I don't get the warning light on at all, static or with the engine running?
The other thing I noticed is, where the garage replaced the belt, they have left the earthing strap touching the fan wheel, which I only spotted tonight arcing out, due to it being dark! Using a mulitmeter, there is no charge going to the battery.
So... Does the dash warning light form part of the charging circuit? Ie if the bulb is gone, will it stop the alternator working? Sounds daft but I know on some older cars this is the case!
Secondly, would the earth strap arcing on the fan/casing damage the diode pack or cause the dash light to blow?
I'm 99% sure the main alternator is working fine, but I am concerned that the earth issue might have damaged somthing else within the system?
Replace the blown bulb for the alternator/battery warning light as it's part of the excitor circuit which powers up the alternator. It's a common problem when the alternator initially packs up, it feeds back voltage in excess of 15 volts which causes the bulb to glow brightly and then blow.
If your unsure about it then as an experiment start the car and apply 12 volts to the small wire going to the back of the alternator. It will start charging straight away untill the engine is turned off and started again when the alternator will need exciting again to enable it to start charging,
NB. Missed the bit about the earth strap which will obviously need to be reconnected first before you try any of the above.
If your unsure about it then as an experiment start the car and apply 12 volts to the small wire going to the back of the alternator. It will start charging straight away untill the engine is turned off and started again when the alternator will need exciting again to enable it to start charging,
NB. Missed the bit about the earth strap which will obviously need to be reconnected first before you try any of the above.
Edited by wolf1 on Saturday 27th November 19:52
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