Time for a new alternator or have I missed something?

[dmdigital]

For a while now my 110 Tdi's charge light has been coming on at startup and staying on until the engine rev's build up enough as I drive off - just backing out of the drive way isn't sufficient. The alternator is putting out about 12.5V after starting and a little throttle as I reverse puts it to about 13.2 - 13.5V. Once I get up to 50kph it's climbs to 14.1V and all is fine until I stop and let it idle for a while and it drops back to 13.2 - 13.5V and the light comes back on.

I put a new Denso alternator in about 3 years ago. Check connections on alternator and I've gone over all the earth points on the Defender and cleaned them up. The battery is 6 weeks old - old one was stuffed after 6 years. I am worried I may have a wiring harness issue as my A/C blew a fuse and the radio also won't work as that circuit also has a blown fuse. I'm thinking the alternator is probably on the way out but I'm wondering if I am missing something else that I should check first.

:confused:

[one_iota]

Hi Derek,

Does your Tdi Defender have a Tacho?

The Disco's tacho needle would fluctuate when the alternator was on the way out (that is if the connection wasn't loose).

[dmdigital]

No it doesn't:( I never got around to fitting one.

[JDNSW]

First thing I'd check is belt tension (probably OK but worth checking), then a loose connection. If nothing found, have the alternator checked by an auto electrician. It is likely that repairs, if needed, would be cheaper than a new alternator.

John

[dmdigital]

Haven't checked the belt, thanks will do that. Connections are all good.


It is likely that repairs, if needed, would be cheaper than a new alternator.
Not here it won't be :(

[OLR-067]

I have a similar problem with my isuzu...new alternator mid 08...charge light comes out when driving and battery indictor goes to right , overcharging. Turn off and light stays on until there is solinoid type noise a minute or do later, or I slam door. I haven't checked it out fully yet, suspect just a loose terminal or earth. One of the many things on the to do list.....

cheers
paul

[TonyC]

I have a similar problem with my isuzu...new alternator mid 08...charge light comes out when driving and battery indictor goes to right , overcharging. Turn off and light stays on until there is solinoid type noise a minute or do later, or I slam door. I haven't checked it out fully yet, suspect just a loose terminal or earth. One of the many things on the to do list.....

cheers
paul

Paul,
My old Isuzu 110 had an external mechanical voltage regulator that has a solenoid in it, I would be checking that that's working OK.

Tony