Why do my lights and alternator gauge dip when it is cold out?

[BushWakr - RIP]

When the engine has been sitting overnight or for any length of time in cold weather a sensor tells the manifold heater relays to send current to the manifold hearter body.

This current draw is considerable and you will see the lights and alt. gauge take large dips on and off accompanied by some "clunking" as the relays kick in and out. That is normal.

The temperature of the intake air will determine how often and how long this heating cycle will run.



Pastor Bob...

 

[CChartier]

wow this is actually the question I was going to ask today. I thought my alternator/regulator, was going out. good to know

 

[hmickelson]

Pastor Bob, I had that problem and thought that the heater took more currentwith the lights on the the alternator was putting out. To cure the problem let it warm up befor turning on the lights full bore or us you block heater. O how sweet it is to get heat almost immediatley Hugh

 

[93 Dually]

Even second and third gens have the same problem but its all good not a prob at all just the preheater sucking juice on cold starts