2002 oil pressure pegged - need wiring diagram

[flyinsquirel]

So it appears that my truck has a wiring harness or at least a partial harness from an 03 and newer LB7 on it. My oil gauge is pegged in about the 3 o-clock position and never moves. I've tried 2 known working clusters and they all do the same thing.

Bought this truck with a bad motor and just got it back on the road. I really don't like driving a vehicle with a non functional oil pressure gauge so I need to get this fixed.

I found a post where it said to ground out the wire and it should swing to zero. Crawled under the truck to try it out and noticed my oil pressure switch connector has 3 wires where an 02 should just be 1 wire. Grounded all 3 wires with no results. Did some checking and found out this is an 03 and newer style connector. I couldn't get a good view of the end of the sender to see if it had 3 or just 1.

So now I need some ideas on how to get this thing working properly without tearing the whole truck apart. I was thinking I could run a wire from the plug that goes into the gauge cluster straight to a new correct 1 wire sensor. I just need to know what wire is the gauge output to the sender so I can tap into it.

Can anyone point me at a wiring diagram or some other resource?

 

[DieselDummy]

Why can't you just get a 3 wire sensor and see if it works? Seems like the next step rather than becoming a wiring expert, I always try the no brainier easy stuff first!!!

 

[MACKIN]

Heres some info that might help not exactly what you want but?


http://www.duramaxdiesels.com/forum/showthread.php?t=12507

 

[TheBac]

Im not even sure an 03 harness would plug into an 02 truck? I didnt think the three-wire sender would even work with the 02 electronics, either.
If either of those is true, then you may also have a wire thats in the wrong place in the main connector.

 

[flyinsquirel]

Im not even sure an 03 harness would plug into an 02 truck? I didnt think the three-wire sender would even work with the 02 electronics, either.
If either of those is true, then you may also have a wire thats in the wrong place in the main connector.

This is what I have found through my research. The 03 and newer sender uses a 5v reference vs a 12v reference for the 02 sender, among other compatibility issues. Maybe the harness was mix & matched in the past, I don't know. Everything else works fine.

So my plan is:

1: Tap into the correct wire coming out of the gauge cluster connector and go straight to a new correct 1 wire sender.
or
2: Tap in at the main connector, wherever that is. I Just need to find out what wire to connect to either way.

I've heard to try gmupfitter for wiring diagrams but the site appears to be down. Any other sources for wiring diagrams so I can find the right wire?

 

[TheBac]

Which other diagram do you need? 02 or 03?

 

[flyinsquirel]

Looking for the 2002. If I could get my hands on one for the main connector and the gauge cluster connector that would be great. That way I could decide what was the better place to connect to.

 

[THEFERMANATOR]

The 02 and 03 trucks use COMPLETELY differrent oil pressure sender set-ups. The 01-02 trucks used the old style 1 wire sending unit hooked straight to the cluster whereas the 03+ trucks use a 3 wire actual oil pressure sensor that sends a signal to the ECM which then sends the oil pressure reading out over the data bus. You need to go and find which wire in your engine harness goes to the pin in the bale connectors for the oil pressure sender and hook it up to an actual oil pressure sender. The 03+ 3 wire unit will never work with an 02 cluster.

 

[flyinsquirel]

I fixed my problem, but am having trouble loading pics right now. I'll get some up later today. Long story short, there was no connection at the main harness as suggested above, and I had a 3 wire sender. Changed it out for a 1 wire, got the wires connected and everything works :woott:

Why everything else works I don't know, but I definitely have an 03 or newer engine harness.

 

[mat]

I am having same problem some pic or help would appriacted

 

[flyinsquirel]

Here you go

http://www.dieselplace.com/forum/76-speciality-forums/81-electrical/442647-2002-oil-pressure-gauge-pegged-need-some-wiring-help.html

 

[mat]

when I click on the link with the pictures message says not signed in.I have a buddy with same problem but can't remember when I fixed mine Thanks for the help