Baffling Problems With Gauge Cluster: Temperature Gauge Peggin'

[s-thetikz]

UK Spec RHD 1990 318is:

My temperature gauge pegs red until ignition (with the key in) and pegs cold when driving.

I tried taking apart the cluster and cleaning the terminals, etc, even tried putting in another temperature gauge from another cluster, does the same thing.

Does this mean the problem is engine bay side?

Car runs great other than the fact that I'd have no clue whether or not the car was overheating. (heater runs hot, when warm, idle good, etc)

Also I noticed when taking apart the cluster that
1. ABS light is unplugged, but I did find a pair of bulbs on a separate wire that went nowhere, although neither light up at start. no abs? i know i should do due dilligence and check another way.
2. oil level warning light? [ oil can with drip symbol ] bulb was missing from the bottom stack of warning lights on the cluster (on the bottom right) but it doesn't light up at start with a good bulb

Thanks in advance!

[reelizmpro]

Try another known good brown sensor first as that's the easiest thing to do. If the problem still persists, then examine the wiring all the way back to the cluster.

[s-thetikz]

Try another known good brown sensor first as that's the easiest thing to do. If the problem still persists, then examine the wiring all the way back to the cluster.

are you referring to the engine aft-side sensor that runs to the gauge? i don't have another known good sensor so i'll have to order one... bosch / febi should be good, right?

after much research i'm thinking maybe the plug connections may have gotten switched with the oil level plug:

where is that in reference to #6 here?
https://www.realoem.com/bmw/enUS/sho...diagId=11_4373

maybe 3 and 1 get switched?

http://repairguide.autozone.com/znet...528004a13c.gif

Actual pic:



diagnostic steps i decided i could take:
1. Edit: DONE --> swap clusters and plug into the car to see if SI batteries can account as a variable (since all i did was swap water temp gauges onto my cluster)
2. take apart top of intake manifold and see if cables are switched (likely culprit?)
3. swapping sensors while i'm down there

hopefully i'm on the right track...

So far:
Definitely not the SI Board / gauges. Burned $100 buying another cluster but oh well, glad I discovered this definitively.

Going to order some temp sensors since they're cheap, debating trying to finger under the intake manifold to swap connectors without taking apart the intake manifold if I can but I can't see much...

[Northern]

I'd mess with the connector from the sensor and see what the gauge pegs cold when disconnected, jumps up a bit with 1.5V from like an AA battery and see if it moves at all.
If it does react then you know the connectors are right and wiring and cluster is probably good.

[reelizmpro]

It's possible connectors for 1 and 3 were swapped if there has been work performed on the car prior to this problem occurring. It's worth a shot. What you refer to as the Oil Level light is actually the Oil pressure warning light. Since you state there's a problem with that also, it sounds plausible the connectors were switched.

[s-thetikz]

It's possible connectors for 1 and 3 were swapped if there has been work performed on the car prior to this problem occurring. It's worth a shot. What you refer to as the Oil Level light is actually the Oil pressure warning light. Since you state there's a problem with that also, it sounds plausible the connectors were switched.

this ended up being the problem. i managed to squeeze my hand under there without having to take off the manifold and swap the connectors. it was an incredibly tight fit and almost looks like it'll snap the wires, but with everything in place the oil pressure warning light now turns on at start, goes off when running and the temperature gauge works beautifully. car runs smoother too.

can wrap this up boyos, finally have a car with functioning vital monitoring. thank you everyone for your help.