Crazy Temp gauge on 92 400E

[F.J.Lahme]

Hello,
I was wondering if anybody has some previous experience with this.
The temp gauge indicator on my 92 400E just started to behave erratically whenever the coolant temperature goes to about 90-100 degree's. It keeps jumping up and down, goes to 120 then down to between 80 and 100, indicates in the red, yet the aux fans do not come on.
Am I just looking at a temp. sensor failure or is there some thing more going on like a fautly thermostat, aux. fan switch or relay( fans come on when I pull the plug with the engine on, but not running).
I thought I'd ask you guys before I go on a replacement odyssey.
Any help would really be appreciated.
Thanks,
Felix

[Benzmac]

Many times we see the wire harnesses failing on these engines. An easy check is to replace the sensor. It is the on on the front of the upper part of the intake. (1 pin sensor)

[F.J.Lahme]

Thanks, that's what I thought I'd try first.
I'll follow up in a couple of days to report if that's what it was.
Thanks again,
F.J.