I have a sending unit for a trans pressure gauge. I'm going to install it. However, it has 2 electrical contacts on it.
Why 2?
Didn't come with directions.

I'd figure just one for sending to gauge.

Is it one for the sending unit to gauge wire and one other for 12v?
Or ground?

:confused:

It may be 1-gauge and 1-light.

Light?

Why would the sending unit have anything for the light?

Is there a check I can do with a meter that might shed some clarity? I'm pretty sure one lead is to the sending unit of the gauge. But the other, must either be ground or 12V.

I can't think of any other reason for a sending unit to have 2 contacts. I don't want to hook it up and apply power and find out its wrong and now I burned it out or something.

Anyone here hook up a trans pressure gauge and sending unit?

Sending units come it two general forms. Typical instrument cluster senders only have a single wire with ground returning through the block. Computer sensors typically have their own sender and ground return leads. It sounds like the sendor you're using may have been used for an ECM application. In general that isn't a problem. It would mean you'd either run a return lead back to the gauge or ground it somewhere on the block or firewall. My only concern would be that it may not be rated for 12V or to directly operate a gauge. Most ECMS are 5V circuits and instead of driving a meter directly they feed into a amplifier / D-A converter circuit that is very low current. Surely it will work fine if the supplier sent them to you as a kit.

Sending units come it two general forms. Typical instrument cluster senders only have a single wire with ground returning through the block. Computer sensors typically have their own sender and ground return leads. It sounds like the sendor you're using may have been used for an ECM application. In general that isn't a problem. It would mean you'd either run a return lead back to the gauge or ground it somewhere on the block or firewall. My only concern would be that it may not be rated for 12V or to directly operate a gauge. Most ECMS are 5V circuits and instead of driving a meter directly they feed into a amplifier / D-A converter circuit that is very low current. Surely it will work fine if the supplier sent them to you as a kit.


Yeah I bought it from Williams Oil Filter service in Tacoma. They said they'd work.
But the leads on the sending unit are not labeled so I don't know which one goes to ground and which goes to the gauge.

Get a digital volt ohm meter and set it on the diode check feature (symbol of a diode or a continuity beeper icon). Measure between the two leads forward and backward. Measure the resistance and repeat. If the readings look the same forward and backward within the same test, then it is a purely resistive sensor and it doesn't matter which line is hot or ground.

If the readings differ between the forward and reverse polarity measurements, post your readings and we may be able to determine which way is correct.

You might look at it with a magnafier to see if there is any symbology or abbreviated symobls on it.

Get a digital volt ohm meter and set it on the diode check feature (symbol of a diode or a continuity beeper icon). Measure between the two leads forward and backward. Measure the resistance and repeat. If the readings look the same forward and backward within the same test, then it is a purely resistive sensor and it doesn't matter which line is hot or ground.

If the readings differ between the forward and reverse polarity measurements, post your readings and we may be able to determine which way is correct.

You might look at it with a magnafier to see if there is any symbology or abbreviated symobls on it.

Haven't had the chance to put a meter on it yet but I did find out that this sending unit is a 'floating ground' type.

VDO 360406 is the part number and I found it on Summit here hoping for some instructions.

http://www.summitracing.com/parts/VDO-360406?part=VDO-360406

I will put a meter on it tonight when I get home from swing shift.

Update:

I received information from VDO and Stewart/Warner.

The floating ground sending unit I have requires one lead to be connected to ground and the other to be connected to the gauge terminal of the sending unit.
Just FYI for anyone that buys a sending unit of this type.

So off I go to the installation stage!

Thanks for the help! :)

M

Update:

I received information from VDO and Stewart/Warner.

The floating ground sending unit I have requires one lead to be connected to ground and the other to be connected to the gauge terminal of the sending unit.
Just FYI for anyone that buys a sending unit of this type.

So off I go to the installation stage!

Thanks for the help! :)

M

And polarity doesn't matter - correct? Must be a resistive sensor.

And polarity doesn't matter - correct? Must be a resistive sensor.

They didn't say anything about polarity, they just said it didn't matter which lead was connected to ground provided that one of them was with the other one going to the sending unit terminal on the gauge.