Dodge 2007 Sprinter Owner's Manual page 268

Problem
The residual engine heat utilization func-
tion switches off too soon or cannot be
switched on. The indicator lamp in the °
switch does not light up.
Possible cause/result
There is insufficient voltage available as too
many consumers are switched on.
What to do if ...
Suggested solutions
Switch off all non-essential consum-
ers, for example the reading lamps,
interior lighting, etc.
The residual engine heat utilization
function will switch back on automat-
ically as soon as there is sufficient
voltage again.
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