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How to Fix Intermittent Temperature or Fuel Gauges in Older BMWs

February 1, 2018

Have An Older BMW With Jumpy Or Intermittent Temperature Or Fuel Gauge?

Does your temp or fuel gauge do this?
* Video credit to BAVauto® friend, Mitch S.

The engine temperature and the fuel gauges are mounted to the instrument cluster circuit board  (The E30 3-series is specifically shown here, but the 3, 5, 6, 7 and 8 series up through the late ’90s and early ’00s have similar issues and are dealt with in a similar way).  They are mounted by a single stud that protrudes off the rear of the gauge. The stud goes through the board (in addition to the two contact pins) and a nut secures it. The stud and nut provide the ground circuit, via their contact on a circuit trace on the board. When the nut is tightened, it makes contact with the circuit trace.  Over time, the nuts can loosen and oxidation can form on the contacts.  Disassembling the gauge from the circuit board, applying DeoxIT contact cleaner and reassembling, will often return the gauge to proper stable operation.  This is not the only cause for the dancing, intermittent or inaccurate gauges, but it is the most common.

DeoxIT (click image):
DeoxIT power booster contact cleaner from Caig Labs BAVauto

BMW E30 temp gauge on circuit board BAVauto
Removing temp gauge from E30 BMW instumant circuit board BAVauto

Disassemble the cluster, remove the nut, and pull the gauge from the board. apply a dab of the DeoxIT contact cleaner/enhancer to each contact point and reassemble.

Applying DeoxIT contact cleaner to BMW E30 gauge terminals BAVauto

Assure that the nut is secure to the mounting stud and also has a drop of DeoxIT before assembly.

BMW E30 temp and fuel gauge mounting stud BAVauto

The above photos show a VDO instrument cluster unit. The MotoMeter unit is similar, but the contacts for the pins look slightly different.

VDO:
VDO BMW E30 instrument cluster circuit board BAVauto

MotoMeter:
MotoMeter BMW E30 instrument cluster circuit board BAVauto


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2 Comments
  1. Johann Spitzer permalink

    E 30 325e 1986 Speedometer some times deads or is dead

    Motometer

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