Alternator dash light not working

[8v-of-fury]

So, I was putting my cluster back in after fixing the odometer gear that likes to slide off.. and now when turning the key on the light does not do its flicker before starting... or its staying on before the engine is revved up and alt excited..

I got out and checked voltage, and the alternator is charging.. but the light is not functioning. I thought the light had to work for alternator to get excited?

thanks guys.

[theman53]

I don't know about the alt. but it sounds exciting to me PUN
Sounds weird. I will be excited to find out what happens.

[8v-of-fury]

thanks for all the help Lucas lol

[rabbitman]

Maybe you bent a pin when you hooked the plug back up.

[8v-of-fury]

possible.. but if the light were not getting any contact.. wouldn't the alternator cease to charge? I have read the LED is very critical to the charging system.. is it not?

[theman53]

Maybe you just cant see it. Maybe it got covered in the process or just went ninja?

[rabbitman]

possible.. but if the light were not getting any contact.. wouldn't the alternator cease to charge? I have read the LED is very critical to the charging system.. is it not?

Yeah I don't know if it's just an indicator or what........Vince'll know!!!!!!

[8v-of-fury]

Pm'ing vince for sure.

[Vincent Waldon]

A couple of thoughts:

1) Every once in a while I've seen alternators that are able self-excite even with a broken D+ wire... probably thru parasitic coupling internally.

2) some VW clusters use a small resistance 1 watt resistor to provide the excitation voltage in parallel with the indicator LED... meaning the LED can be out and the alternator will still function. 

The LED actually rarely burns out... more often the issue is a cold solder joint on the circuit board itself.  It's possible moving the cluster dislodged an already weak joint?