200 amp dual voltage regulator

Just got my '89 M998. I noticed at night my lights pulse. This pulsing is in conjunction with the gauge in the cab. It pulses from a good charge to an overcharge. Sometimes it stops after a couple of minutes which made me think it was the glow plugs cycling. The other day it did this for the entire 20 minute drive. Found this sure and started reading. Downloaded a ton of manuals. I have checked all the power connections for cleanliness and security. Armed with this information I found the regulator hooked up for dual voltage use but the 14v output is grounded to the case. Could this be the pulsing issue? Why would someone hook this regulator up like this? Any information is appreciated.

If its a V belt truck and a regulator is older than 2012, then It gets grounded....[14v tap ].

Thanks. Anyone have an idea about the pulsing? I haven't load tested the batteries yet.

Sgtmurtaugh said:

Thanks. Anyone have an idea about the pulsing? I haven't load tested the batteries yet.

Click to expand...

The pulsing is glow plug after glow from your EESS box. Will do this for 2 min after cold start or anytime the
Glow plugs were energized from being below 120 degrees engine temp.
its normal...if you don’t like it, upgrade to the S3 EESS box, they did away with the pulsing.

Does the temperature gauge get it's signal from the glow plug controller?

Sgtmurtaugh said:

Does the temperature gauge get it's signal from the glow plug controller?

Click to expand...

no

Problem solved. Dirty connection at the glow plug controller. Pulsing is no more when engine reaches 120 and the volt meter maintains position!