Heater/electrical problem?

[Chevy305]

On occation when I turn the heater on in my truck I see the little battery light illuminate ever so slightly. Its only noticable at night. The higher I put the fan the more bright it gets. It does this intermitantly. If I turn off the heater the light goes completely out. Also my volt gauge reads steady up around 15-15.5 volts. What could be causing this? Any ideas?

 

[NEK5]

Bad ground? Wouldn`t hurt to check all your grounds...

 

[dirtynails]

I have had exactly the same problem on my 83 for over 100K miles now. I posted it up here did every they're about to tell you. All of which is correct. It would be nice to finally know what the real deal with it is, but so far I can't say it's caused me any problems.

 

[Chevy305]

hmmm....

Thats interesting, I guess its just one of those things...