how about some pointers on checking out the voltage regulator? I know how to check the battery and alternator with a volt meter, but am clueless on how to test the voltage regulator...

thanks,Mark

I love hearing about your posts the the progress with your sons car. If you understand checking battery and alt with  a multimeter I would suggest two things.

First check your grounds. The issues that you have pointed to with corrosion problems suggest that this could follow through to grounds. 

Then if battery, alt (stator and rotor) and grounds are right by default. An alternator will have both regulator and rectifier. Diods and conection and should be easily checked with a good multimeter. Check and eliminate by defalt.

I thought that this era Merc sould still be running a generator?

Cheers

Warren

this year has an alternator, but also a voltabe regulator as well as an instrument panel voltage regulator...

thanks again, Mark

Another thought: Take regulator and alternator out & take to an auto parts store where they have "free" testing; probably easier than "hunting" around; and, will either give you definitive answers, or eliminate those parts as being the cause of the issues.

Me, I'd probably keep "hunting" for my own satisfaction; but, it'll probably be a better use of time to get them tested; I just need to keep learning that lesson!

Regards,   JLB