Offroad-Express

I noticed the other day that the check engine light and battery lights on my dashboard are on but very feint. The vehicle did get wet on the passenger side but I pulled out the ECU and dried it in the hot water cupboard for a few days.
- Had the battery checked and it's fine.
- Alternator seems to be working, charging at 13.5 volts with all the lights and wipers on.

Anybody had a similar problem? Could it be the ECU playing up?

Someone might correct me, but I think your alternator should be around 14.5v shouldn't it?

Charging voltage does sound a bit low.

Anything over 14V is acceptable for a good alternator.

13.5v is ok with a load on the alternator, not ideal but ok. I expect it still has some moisture somewhere to bring the lights on dimly. Probably in a connector.

On my '93 L200 there is a rheostat knob that allows you to vary the dashboard brilliance next to the demister on/off switch. Check this as you may have turned it down.

Whenever my batt light is glowing very faintly its the alternator, only notice it when parked in the garage in the dark with engine on, does it go away with revs?

Each time the volt meter was still reading ok.

A poor or dirty earth wire contact can cause your dash lights to stay on dim. Check all the earth points, But you output voltage on your alt is on the low side, so alt could be on its way out