Oil pressure gauge wiring

[acesneights1]

My deuce has low oil pressure and think there is a gauge issue. Truck came to me with a Faria that was stuck all the way right. Upon removal looked like top of it was melted. I smacked it and needle went left. I took an older period correct gauge(SW I think) from another one and put it in and now it goes to 30 and does not move much at higher than idle which seems low to me.
lookimg at this schematic it shows 27 as power ? And 36 to sender but in reality it seems like 27 is for illumination.
yes I do have it grounded.
http://www.steelsoldiers.com/showth...uce-schematic!&p=354820&viewfull=1#post354820

 

[acesneights1]

Also gonna put a test gauge on it tonight but just confused how it gets power if 27 is supplying the illumination.

 

[Carl_in_NH]

27 is instrument power. 49 is illumination, according to the schematic.

 

[Barrman]

The M35 gauges don't have illumination wiring. They have power and they have a sender wire. Ground is through the panel screws which is often a cause of erratic gauge readings. Illumination is from the clear sides in the gauges getting fed red light from the two lights for the entire gauge panel.

Wire # 27 is supposed to be power into the all the gauges through the multi legged wiring harness secured to the back of the speedometer. Often called the "spider wire." When sitting in the cab, looking at the dash. The power in wire is on the left of all the gauges.

Wire #36 goes from the gauge to the oil pressure sender.

Wire # 40 is the instrument panel light circuit.

Here is a list of all the wires and what they do:

http://olive-drab.com/od_mseries_circuits.php

 

[doghead]

the 0-60 and 0-120 gauges use different sender units.

Check what you have is matched to the gauge.

 

[Carl_in_NH]

I find it interesting that the Olive-Drab numbering and the linked schematic are clearly in disagreement with each other when it comes to the illumination circuitry numbering. Anyone know which one is correct?

 

[acesneights1]

the 0-60 and 0-120 gauges use different sender units.

Check what you have is matched to the gauge.

Hmm....someone did put the newer Faria gauge in but it was not connected. Anyway to tell the difference in the sending units themselves ?

 

[acesneights1]

The M35 gauges don't have illumination wiring. They have power and they have a sender wire. Ground is through the panel screws which is often a cause of erratic gauge readings. Illumination is from the clear sides in the gauges getting fed red light from the two lights for the entire gauge panel.

Wire # 27 is supposed to be power into the all the gauges through the multi legged wiring harness secured to the back of the speedometer. Often called the "spider wire." When sitting in the cab, looking at the dash. The power in wire is on the left of all the gauges.

Wire #36 goes from the gauge to the oil pressure sender.

Wire # 40 is the instrument panel light circuit.

Here is a list of all the wires and what they do:

http://olive-drab.com/od_mseries_circuits.php

I could swear when I unplugged the 27 wire the light went out but been working long hours and my memory isn't so great.
i'm trying to get this truck and my 813 whipped into shape by May for a big fundraiser for a Marine Corp detachment.
been working long hours on them and a third deuce owned by a close friend who is also gonna do the fundraiser.

 

[doghead]

Clean and read the sender, it says what it is. iirc...

 

[acesneights1]

Clean and read the sender, it says what it is. iirc...

Yep, that is where it was and that was my problem.