1995 C2500 ls1 swap

[chvy=power]

Looking good! That new engine should be fun! I ended up flaring the stock steel lines for -6AN. But that braided stainless sure does look good. I also reused the stock fuel filter bracket which made the foam look like poo. I'll do what you did if I ever swap filters. I'll be watching your build and chime in wherever I can help. I also have a 95.

Thanks man! yea iv never been any good at flaring anything, so thats why i went the route it did lol...
Question...im splicing in the fuel pump wire from my nelson harness to the factory wire for the fuel pump...now before i cut and splice, just want to double check and make sure that the purple wire is the one I want to hook to?

[Jeebalow]

Thanks man! yea iv never been any good at flaring anything, so thats why i went the route it did lol...
Question...im splicing in the fuel pump wire from my nelson harness to the factory wire for the fuel pump...now before i cut and splice, just want to double check and make sure that the purple wire is the one I want to hook to?

I actually hooked the fuel pump wire from the LS pcm to the signal wire that activates the stock 95 fuel pump solenoid. Is that a signal wire from the PCM or is it power that should go directly to the fuel pump? If it's power, the wire going to the fuel pump is gray. Let me grab a picture of the underside of my fuse box.

Edit- here it is. You'll notice the 5 wires on the bottom left of the picture. Those all go to the 95 fuel pump out relay. Green and white is the signal from the PCM, red is the stock pump prime signal, orange is battery power (hot at all times), black is ground, and the gray one that is almost hidden is the power wire out to the fuel pump.

[chvy=power]

Na the Nelson harness has its own fuel pump relay. It has a pretty healthy power wire that hooks to, feeds voltage to the pump. I guess what I'm asking is the stock 12v power wire for the fuel pump a purple wire?

[Jeebalow]

Look at my previous post. I edited it, but you're too fast haha

[chvy=power]

Ah gotcha. So the grey wire in this harness is the one Im looking for

I guess the other 2 wires are for fuel gauge?

[Jeebalow]

Ah gotcha. So the grey wire in this harness is the one Im looking for

I guess the other 2 wires are for fuel gauge?

Yes grey comes from the relay. Purple goes to the fuel gage, not sure what black/white does.

[Jeebalow]

I'll reply to your PM here so the info isn't hidden and someone that searches can see it.

so im finishing up the wiring on my 95 swap...im using a nelson harness and it has a green speedo wire. Iv been told to find the DRAC module behind glove box on pass side, remove harness, snip blue wire w/black stripe and red wire /black stripe and hook them together then hook to my green wire from nelson harness. Is this what you did?

The drac on my 95 doesn't have those colors and I am willing to bet yours doesn't either. Here is what the wire colors for mine (95 C1500) are and what they do

Dark blue - to 95 PCM
Dark green - to gauge cluster and spare cavity convenience center
White - brake pressure modulator
Purple/white - VSS in
Brown - to 95 PCM
Pink - Fuse 4 (Gauges)
Black/white - Ground
Green/black - VSS in
Dark green/white - cruise control module and stereo

So if you just want to get the speedo working you can splice into the dark green wire anywhere along the wire. You can do it at the drac or behind the cluster.

Here's what I did. I took the dark green/white and dark green wire and spliced those together and connected them to the dark green speed wire from the LS PCM. So both speedo and cruise control module get speed signal. I am assuming that they both use the same signal and that these were the red/black and lt blue/black wires they spliced together, but am not 100% sure yet. I still haven't gotten the truck on the road to verify whether this works. I guess we'll find out soon enough. Feel free to give it a shot and let us know if it does work.

[chvy=power]

I'll reply to your PM here so the info isn't hidden and someone that searches can see it.



The drac on my 95 doesn't have those colors and I am willing to bet yours doesn't either. Here is what the wire colors for mine (95 C1500) are and what they do

Dark blue - to 95 PCM
Dark green - to gauge cluster and spare cavity convenience center
White - brake pressure modulator
Purple/white - VSS in
Brown - to 95 PCM
Pink - Fuse 4 (Gauges)
Black/white - Ground
Green/black - VSS in
Dark green/white - cruise control module and stereo

So if you just want to get the speedo working you can splice into the dark green wire anywhere along the wire. You can do it at the drac or behind the cluster.

Here's what I did. I took the dark green/white and dark green wire and spliced those together and connected them to the dark green speed wire from the LS PCM. So both speedo and cruise control module get speed signal. I am assuming that they both use the same signal and that these were the red/black and lt blue/black wires they spliced together, but am not 100% sure yet. I still haven't gotten the truck on the road to verify whether this works. I guess we'll find out soon enough. Feel free to give it a shot and let us know if it does work.

awesome man thanks for the clarification! Ill pull the drac harness out toning and take a look at it...im still about 2-3 months away from firing it up. Just sent the L92 heads off my LY6 to TEA to get a little work done

[Mickeymotormount]

My '93 wires are different colors. I didn't use the buffer since the PCM has the buffer included inside it(or doesn't use it at all). I ran the cruise wires from the PCM directly to the cruise control module. The only thing I had to get was the brake input to shut down the cruise when the brake is applied. I got this from the rear ABS module which is in close proximity to the cruise module.

[Jeebalow]

My '93 wires are different colors. I didn't use the buffer since the PCM has the buffer included inside it(or doesn't use it at all). I ran the cruise wires from the PCM directly to the cruise control module. The only thing I had to get was the brake input to shut down the cruise when the brake is applied. I got this from the rear ABS module which is in close proximity to the cruise module.

Can you elaborate on the cruise control wiring? What pins and connector do they come from on the PCM and what year engine are you using? My 95 has a standalone cruise module and the only signal missing to it (since I removed the drac) is speed signal, that is why I spliced the two wires together at the drac.

It's also worth mentioning that I got rid of both the DRAC and old ECU.