2003 Chevy 1500, 4.8 engine. The oil pressure gauge reads all the way to the right (80 lbs) when key is on or engine running. Turn the key off and it goes to zero. I would like to know what the true oil pressure is without replacing the instrument cluster. Can you still come off the sending unit and install an auxiliary gauge like you could on the older vehicles? If so, where is the sending unit on this truck?

Also, the blower speed control (1-2-3-4-5) now only works on 5, after losing the others one at a time. What is the fix for this?

thanks, Wingnut

most likely, the oil pressure sending unit is bad, or at least that is the most common problem I see on the trucks i work on

the blower problem is going to be the blower resistor and probably the connector is melted also. It happens when the blower motor draws to much amperage

ac problem bubba is right look under your dash on the passenger side you will see your problem you will have 4 melted wires

The is a oil pressure sending unit connection of an auxillary pressure gauge on your oil pan just disconnect the connector and attach your pressure gauge. the a/c sounds like what lureklr described check your wiring

thanks for the help, will check it all out

Unfortunately, Jonboy, you are incorrect.
The sending unit in the oilpan is a low oil level sensor. there is no oil pressure
present in the oilpan.
Thanks for playing, though

on a more serious note, both observations are right on, but there have been guage problems in gm clusters for decades. 9 out of 10 it'll be the sender, though.
good luck & let us know how it turns out

Just be glad it is not on a 1992 GMC truck!

I replaced the faulty sending unit and had to remove THE DISTRIBUTOR to get a tool on the blamed thing!

Folks on here and other sites kept saying...."OH, you can just slip the wrench over the sending unit and take it right out, a piece of cake!"

NOT! There is only ONE INCH OF CLEARANCE between the unit and the firewall!

Maybe the advisors meant for me to cut a hole in the firewall FIRST and THEN use the wrench! Hmmmmmmmmmmmmmmm!

I think you should replace the sending unit.

You're right there is little room behind the dist. for access to the sender. Having worked on commision for Chevy dealers for more than 20 years ya tend learn the tricks. If it happens again get the correct socket for the sender and a flexable(adustable head)ratchet. Borrow if ness. Its tight but you can get it out w/o removal of the dist. Trust me.

After finally getting time to do so, I pulled the blower resistor yesterday and it is fried. The wires and plug are good. I ordered the part on line, and soon as it comes in I'll be back in the blower business. Thanks Bubba and Lureklr for the help on this!

Now, to try to find the sender through my trifocals. . . .this ought to be good. . .ha! I guess it is back there somewhere between the back of the engine and the firewall?

wingnut- I think the o/p switch is on the side of the oil filter mounting boss on the new v-8 engines, as the block is a completely redesigned part.
In addition, you can buy the DEEP oil pressure switch socket @ Autozone & just ratchet it out.

The oil pressure sending unit on your engine is located behind the intake, on the block. It is right next to the firewall. If you have a deep 1 1/16" socket, a wobble, and an extension, It is not a big deal

Thanks, bubba and lite-liner. Will have to replace it later since my son left to go back to college in the truck. Wing