LS Swap into 1997 Chevy 1500

[JustinL]

Hi Everyone,
I will try and make this as detailed as i possibly can as i have been on both ends of these forums for other cars for quite some time and i can understand how annoying it is to have mis-information or bits missing.

What i have:
1997 Chevy 1500 4.3L Regular Cab Regular box 2wheel drive.

What i did:
1. took out 4.3 (upper manifold gasket blew and leaked coolant everywhere cooking the engine)
2. replaced 4.3 with a 5.3 out of a 2000 chevy 1500 (LM7)
3. installed 5.3 with the 5.3 computer and fuse panel and engine harness that came with the engine.


Info:
1. Using a 4l60e transmission with an added oil cooler.
2. Using the old computer to run brakes and gauges.
3. Using new computer to run new engine and hopefully speedometer/tach.
(got the guy at lt1swap to convert some signals to work with my dash ect)


Issues...
1. Speed signal for speedo
I have wired PIN 50 from the Red (C2) block coming from the new 2000 ECM to the old body C100 plug (pin B5) that has the same wire colour and supposedly is the "vehicle speed sensor". When i use a voltmeter and test this connection it sends out voltage as it should. The issue seems to be with the dashboard reading the information.


2. Tachometer
I have wired PIN 10 from the RED (C2) connector coming from the new 2000 ECM to the old body C100 plug (Pin E8) that has the same wire colour (white) when entering through the firewall. I have tested the signal coming from the new ECM that you programmed and the higher the REVS the higher the voltage it puts out.
For the tach to work… are there any other wires that need to be connected? I havn't touched the dash since the swap. I HAVE cut most of the wires that come out of the C100 plug though. The only wire that seems to matter though for the TACH is pin E8 though. Can you shed some light on this?

3. Fuel Gauge Sensor
I have wired Pin 54 from the RED (C2) connector coming from the new 2000 ECM to the old body C100 plug (PIN C2) that has the same wire colour (purple) when entering through the firewall. This signal comes from the fuel tank sender I assume and goes to the new computer. Am I correct in connecting PIN 54 to the dash for the fuel gauge sensor?

P.S I have gotten the water temp and the voltmeter on the dashboard to work correctly. So I can assume??? That the power and ground for the gauges is connected and I am only having to worry about the signal wires. From the wiring diagram I can see that the power and ground is shared across all the gauges??
The backlighting for the dash panel is also not working.
which wires control the backlighting?
If ANYONE has a pinout diagram for the little connector at the back of the gauge cluster i would be super happy. I cannot find one that fits for the life of me.


If i am missing anything i appologize... i have been both banging my head against the wall and pulling my hair out at the same time. I am so close to just giving up and buying a set of autometer gauges and wiring them up as i know i can make those work.. my preference is to get the stock stuff to work though.

Thank you in advance guys... first post here.... Be nice :P