They are both part of the same armature and it doesn't look like either one
is bimetallic, just heavy copper

--

73
Hank WD5JFR...
"Jamie" wrote in message
...
Henry Kolesnik wrote:

The glow plug relay on my diesel Mercedes, an 83 300SD has two sets of
parallel contacts but only uses one because the other has a gap of about
0.035" when the first set closes. I thought this was due to improper
alignment and I bent the other arm so that both would make contact. The
other day I found another relay and noticed that it had one set of
contacts spaced so they didn't close. Are there any experts out there
that can tell why they do this? My guess is that the open set is a spare
for when the first set wears too much. But that doesn't make sense
because two sets working in parallel wouldn't wear as fast. Also would
like to know if anyone has reversed engineered the circuit as it has an
IC and a couple transistors. The circuit acts as monitor to make sure
glow plug no. one is drawing current and then turns a dash light
indicating that the plugs are heating and when it goes out in a few
seconds it OK to hit the starter.
tnx

are you sure the other arm isn't some kind of termomatic timer? are they
connected together ?