SJ Alternator woes (Strange problem)
Posted: Mon Sep 15, 2014 9:01 pm
Having a bit of a head scratcher here. Hopefully somebody can clear this up for me before I fork out on a new unit.
Truck was running fine. Went off road Sunday, ended up bonnet deep in muddy water. Dragged truck out, wouldn't fire on starter, tow started it, and drove it home.
All the way home, the battery light was coming on at lower revs. Not sure what RPM as I don't have a rev-counter. But I'd say it was anything below 1/2 maximum revs, whatever that is, the light would come on.
So I instantly assumed it was the alternator on it's way out.
Got home, parked SJ up. Went out this morning, and it fired up after a few goes, very reluctant though, starter motor was jamming up.
After work, it wouldn't go at all, but went on a push start.
This time around, there was no warning light on the dash at all. Not when it's on 2'nd stage ignition, and not when it was running either.
Managed to get it to my garage. I stripped the Starter Motor, cleaned it all up inside as it had all corroded inside. Works fine now.
Then started the thing up, whacked the multi-metre on the battery... 12.4v constant. No charge, no fluctuation of voltage.
Removed the main alternator terminal, and tested the alternators output. It was giving under 2 volts.
So I whipped it off, stuck another alternator on I have spare. Which I was sure worked before I removed it from the 410 engine.
Exactly the same. No warning light at all, and no charge from the alternator.
Now I started to investigate, and I am not sure if the following is normal.
Ignition off:
Red/White wire - 0v
Black/White wire - 0v
Ignition on:
Red/White wire - 12v
Black/White wire - 12v
When I give the red/white wire a negative with the power probe. Dash warning (battery light) comes on.
Once the engine is running. Both red/white, and Black/white wires stay at a constant 12v, and when I whack a negative down the red/white wire, the battery light comes on again.
Terminals on the alternator, what I can gather, is top one is a dummy, one closest to engine is for battery warning light, and one furthers from engine is switched live?
If so, then the switched live one does nothing. The power probe doesn't register it as a live, or an earth at any time. So is this saying that both alternators are knackered?
Any help much appreciated.
IF, the alternators are both dead, then I will probably go over to a bigger one. What do people use?
Truck was running fine. Went off road Sunday, ended up bonnet deep in muddy water. Dragged truck out, wouldn't fire on starter, tow started it, and drove it home.
All the way home, the battery light was coming on at lower revs. Not sure what RPM as I don't have a rev-counter. But I'd say it was anything below 1/2 maximum revs, whatever that is, the light would come on.
So I instantly assumed it was the alternator on it's way out.
Got home, parked SJ up. Went out this morning, and it fired up after a few goes, very reluctant though, starter motor was jamming up.
After work, it wouldn't go at all, but went on a push start.
This time around, there was no warning light on the dash at all. Not when it's on 2'nd stage ignition, and not when it was running either.
Managed to get it to my garage. I stripped the Starter Motor, cleaned it all up inside as it had all corroded inside. Works fine now.
Then started the thing up, whacked the multi-metre on the battery... 12.4v constant. No charge, no fluctuation of voltage.
Removed the main alternator terminal, and tested the alternators output. It was giving under 2 volts.
So I whipped it off, stuck another alternator on I have spare. Which I was sure worked before I removed it from the 410 engine.
Exactly the same. No warning light at all, and no charge from the alternator.
Now I started to investigate, and I am not sure if the following is normal.
Ignition off:
Red/White wire - 0v
Black/White wire - 0v
Ignition on:
Red/White wire - 12v
Black/White wire - 12v
When I give the red/white wire a negative with the power probe. Dash warning (battery light) comes on.
Once the engine is running. Both red/white, and Black/white wires stay at a constant 12v, and when I whack a negative down the red/white wire, the battery light comes on again.
Terminals on the alternator, what I can gather, is top one is a dummy, one closest to engine is for battery warning light, and one furthers from engine is switched live?
If so, then the switched live one does nothing. The power probe doesn't register it as a live, or an earth at any time. So is this saying that both alternators are knackered?
Any help much appreciated.
IF, the alternators are both dead, then I will probably go over to a bigger one. What do people use?