I recently replaced my instrument panel with the upgraded one with the tach and guages. Almost everything works but the oil pressure guage. I did replace the sending unit with the guage type sender, and was careful to disconnect it before hooking up the new panel. I do have a multimeter and would like to know if someone can give me the values I should be reading from the sending unit. It was a used one and not sure if it is good. TIA Roy

An easy way to tell if the gauge is working and the sender is not, is to take the wire off the sender, and ground it. Turn the key on, and the gauge should peg itself, reading 100% oil pressure. If not, you have a bad gauge or bad wire.

DO NOT DO THIS!!!

It will ruin the gauge in the cluster.

Hmm. I did not know that. Thats the way I've always been taught at work. Been doing it for a while and never had a problem. isn't the gauge basically reading resistance of the oil pressure sender? When you ground it, it reads maximum resistance. I don't see how that hurts it.

The stock Toyota gauge does not operate in this way... It sends the reading via a pulsing frequency of grounded/non-grounded. The grounding is still somewhat resisted, and occurring at a frequency fast enough to only allow the gauge windings to heat up a small amount.

Grounding the gauge wire on your Toyota will overheat the gauge windings and permanently distort them. The windings will bend upon contact with the upper limiting peg, and will never rise again (the bend will make normal operation rise only to th level of the peg, anything less will just force it down on the bottom limit peg with more force).



There was a post a while back on the proper way to test these sending units... It was pretty in-depth, and covered all the different types of sending units and gauges. If I have time later, I will search it up, but it might be a couple of days.

Search can be your friend, if you can get it it work right... Which brings up another subject... I noticed I cannot search up a certain thread of mine from 2004... I manually looked, and I can't find it, either. Nothing was against the TOS in it, and I did not delete it... It seems the board lost a bit of history somewhere along the way.

OK, I see.

The FSM shows using a LED light inline with battery voltage. Doesn't specify the value of the LED, don't know if that matters.

A 12v test light will work fine.
There seems to be several different kinds of pressure senders.. At least two for the "guage style" switch itself.

As mentioned above, grounding the connection directly is a bad idea. Grounding through a test light is ok as it limits current.

The aftermarket senders I've bought aren't the pulse type, they seem to be pressure/impedance related.. My factory guage doesn't quite work right either.