Manntis

are they on the same circuit? Both seem well connected to sensors...

Manntis

nada?

Rogue_Wulff

I don't know about them being on the same circuit, but the wires do branch off the main harness at the same location. I think I heard someone say there is a plug somewhere in this part of the harness, on later model cars. Maybe it's just on the SE
I would start by checking for power at the connections to the sensors, and trace it back from there. Power at the senders, bad senders or ground. No power, something amuck in the wiring.

darkfrost

iTrader: (1)

If you re-installed them recently and used too much teflon tape, it can prevent the senders from grounding.

trochoid

iTrader: (6)

That's why I use teflon paste.

j9fd3s

iTrader: (3)

the gauges except the speedometer are on the 'meter' fuse.

we did have one customer who plugged them in backwards after an engine swap, if you had it apart recently, thats likely.

if you nobody worked on the car, and they just done work, prolly not. maybe the ground is the same?

Manntis

plugged them in backwards as in the wrong connectors to the wrong gauges, or simply swapping the + and - at the sending units?

trochoid

iTrader: (6)

Both sending units are single wire with different connectors. Does the rest of the dash gauges/lights work?

Manntis

everything else in the binnacle works.

The coolant sensor is all the way over by the waterpump - is the common ground inside the harness wrap?

Rogue_Wulff

The coolant temp sensor is right above the oil pressure sensor. Both are just below the oil filter.......

cdrad51

The coolant temp sensor by the water pump is for the choke. Like Rogue said, the coolant temp sensor for the gauge is below the oil filter.

Manntis

Wierd - my factory manual just identifies the one @ the pump as the coolant temp sensor. BTW I have an SE, fuel injected.

So the small sensor just below and in front of the oil pressure sending unit is the coolant temp sensor for the gauge - but as trochoid mentioned these sensors have unique plugs and are single-wire. I assume they ground through the block, so I'm not sure why both are failing. The plug attached to the oil sensor is showing 7 volts - should it be 12?

MosesX605

It should be noted that the oil pressure gauge moves to the extreme right and stays there but the water temp guage doesn't even move. One suggests a bad ground and the other a bad connection, IMHO.

Rogue_Wulff

Bad grounding thru the block, or bad sender. The other is a bad connection, or broken wire.

It is a coolant temp sensor, for the ECU. Unplug that, and your SE will flood like a pig.

Touching the wires to the engine block (key on) *should* cause the gauge to climb to it's highest reading. If this does occur, you either have a bad ground where it threads into the engine, or a bad sender. If it does not occur, the problem lies in the wiring, or the gauge itself.

Manntis

Okay, so one wire went to the oil pressure sending unit, with a unique connector. Another went to the smaller coolant temp sending unit, below the oil filter. A third went to something that appears to be a capacitor attached to the back of the engine block right by the top of the bellhousing.

Turns out the connector for the coolant sensor and for the 'capacitor' are the same shape - I swapped them, and now both the coolant and oil gauges work. Go figure.

trochoid

iTrader: (6)

Interesting, glad you figured it out.