1994 to '95 Dash Swap Cluster Question

[stevestoffer]

Hey guys, I have a '94 Crew Cab that had a 6.5L in it. Right now it's getting a Cummins swap and I have no wiring done. I decided to do a dash swap while I was at it so I found a 95 dash. I used the 94 wiring harness, wired in the lights, switches, new radio, and I'm using the old steering column and the old heater control. My question is, if I get a 6.5L gauge cluster out of a 95+, is all of the wiring the exact same for the cluster as the 94 one? So if it is, can I just plug it right into the 94 harness and it will work?

Also, for the gauge wiring in the Cummins, do the gauges run off of the computer or what? I'm planning on getting rid of all the wiring for the computer just to make it nice and clean behind the dash, but if my gauges run off of the computer or something then I have no idea what I'll do haha.

Sorry if these questions are dumb, this is my first project. I literally knew nothing going into it but I've learned a lot. Now all I need to figure out is the wiring and I know how to finish the whole project! Thanks guys!

 

[95Suburban]

As for the cummins gauges, it depends on what generation motor you are using. If it is a 12v then there is no computer at all. 24v and newer has its own computer (ecm) and needs inputs from oil and temp to run, however, they use a different language than what the Chevy and aftermarket gages use. So you can't just tap into those signals. You will have to find new places for your oil and temp sending units. But they are easy to find.
You will also need to use the 6.5 alternator with the 6.5 gauges in order for the tach to read correctly. I tried a gas one in mine and it was way off, had to switch back to the original.
I put a 24v in my 95 Suburban, I learned a LOT.

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[cjman250]

You will need the computer to control the transmission

Sent from my awesome S5

 

[stevestoffer]

Running a Ford ZF 6 speed behind the Cummins. It's a 12v P pump motor. I guess I will get a 6.5 alt. Are those internally regulated? I think they are... But my main question was will a 95 6.5 gauge cluster work on the 94 wiring harness with the 95 dash? I was doing a dash swap while I was at it and I thought the 94 cluster was the same height and width as the 95 but it's not. So I was just going to get a 95 and up 6.5 cluster, but I want to know if the wiring for the speedo, tach, etc are the same wiring as the 94 cluster, so is it just plug and play is what I'm asking. (Forget about the Cummins swap for now, say I was swapping a 95 dash in my 94 6.5l truck) Thanks for the replies!

 

[stevestoffer]

And for the computer question I know the 12v doesn't need one at all but I was asking if the gauges ran off of the computer when they were used with the 6.5. I sold the computer and engine wiring harness with the motor, I can always get a new one and wiring for $5 out of the local junk yard if I have to but I want to keep the wiring as clean as possible. I go nuts over wiring haha.

 

[95Suburban]

Gotcha now. I'm not sure on the 94, but my 95 all my gauges ran through the pcm. Speedo, tach, oil, water, and I think the battery too. I wanted to get rid of it as well but needed to keep it or go all aftermarket. Even the cruise control is run by the pcm on mine since this truck was fly by wire.
The 6.5 alt is internally regulated.

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[Biggershaft96]

You should do a build thread with lots of pics!!!!

 

[stevestoffer]

You should do a build thread with lots of pics!!!!

Well I already have 2 build threads so I kind of don't want to start another... But I'll post a few pics here.

Here is the Cummins and ZF6. I had an adapter plate custom made and I have a Southbend dual disk street clutch good til 750 HP.

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Here it is after it was dropped in.

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I did a SAS on it too and that gave me about an 8 inch lift, then I had to run a 3 inch body lift for the Cummins to fit. Here it was in the fall, with the original Cummins I was going to use. (It was a first gen with Getrag but I got a deal on my P pumped motor so I took it out and sold it).

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I'm going to move the rear axle back about a foot or so, lift the rear, then make a flat bed for it. The flat bed will have the body line in it like some nice welding beds. I also have the K1500/2500/3500 tow mirrors on it from the newer trucks. I also have crossover and high steer on it and I'm going to run hydro assist. It also has a knuckle tie in kit haha. I'm also taking some cab lights off, because it has too many I think lol. Still far from done but I hope it will be able to drive in a few weeks here.

Oh and I'm building it to about 600 HP. I have compounds coming soon!! I'm just going to run an HX35 and HT3B for now, but maybe next year I'll have a more serious turbo set up.

 

[great white]

Ok, you're dealing with a couple issues here since you're crossing the 94-95 years and the whole gas diesel thing.

94: OBDI. Gauges are pretty much stand alone. The ecm doesn't process the signals like in OBDII. Speedo uses a DRAC to condition the signal from the VSSB. Gassers and diesels are essentially the same except for the tach. Gasser tach runs of spark, diesel tach runs off alternator.

95:OBDII. Gauges run through the PCM. Pretty much all of them. Gassers and diesels are different. Diesels soldiered on with same setup as OBDI (gauges that is)

So, here's what I would recommend.

The 95 and 94 interiors are different physically so a diesel cluster is not going to "drop in". Either physically or electrically. Swap the entire 95 style dash in and you can at least use the 95 style cluster.

You're not using the GM transmission or the engine in the 94 chassis. The 1994 ECM can go. (Save it though, it's worth a couple bucks. It should have the 7427 PCM, which is a fairly sought after OBDI PCM)

The speedo requires a 40 PPM vssb signal. I'm not sure if the ford transmission has one. The diesel cluster requires a DRAC/VSSB to condition the signal. Fuel gauge runs directly of the fuel sender. Tach off the alternator windings. Oil pressure can run from a stand alone sender on the 12V. Ditto with the coolant temp gauge.

Cruise isn't going to work from a diesel since it is all done in the PCM. You can use the cruise off your 94 gasser since it is a a standalone module that uses a signal from the DRAC/VSSB. You'll have to "rig up" a bracket and a way to connect the cable to the throttle.

Wiring is going to be a mess. You'll have to sift through that and make it work somehow. Problem is, you're crossing gas/diesel, OBDI/OBDII years, the interior change years and even Ford/GM. It's do-able, but you are going to have to sit down with a couple different wiring diagrams, wire cutters and a soldering iron to make it work.

It's almost worth your while to just create a new wiring harness altogether.....

I would probably strip out the wiring harness completely and install a diesel harness. That would be the quickest way to get most of the wiring and components you would need to get the cluster up and running. Use a 95+ harness (preferably 96+ since 95 is a bit of an odd ball year) and the rest of the 95 interior bits will plug right in. You won't need the PCM from the diesel to run anything either. I'd probably grab the entire truck harness from a diesel actually. Closer all around to what you want since all the systems are pretty much stand alone. Instead of figuring out where to splice what, it's find which circuits you don't need and just strip them out.



Good luck, I don't envy you.

 

[stevestoffer]

Ok, you're dealing with a couple issues here since you're crossing the 94-95 years and the whole gas diesel thing.


94: OBDI. Gauges are pretty much stand alone. The ecm doesn't process the signals like in OBDII. Speedo uses a DRAC to condition the signal from the VSSB. Gassers and diesels are essentially the same except for the tach. Gasser tach runs of spark, diesel tach runs off alternator.

95:OBDII. Gauges run through the PCM. Pretty much all of them. Gassers and diesels are different. Diesels soldiered on with same setup as OBDI (gauges that is)

So, here's what I would recommend.

The 95 and 94 interiors are different physically so a diesel cluster is not going to "drop in". Either physically or electrically. Swap the entire 95 style dash in and you can at least use the 95 style cluster.

You're not using the GM transmission or the engine in the 94 chassis. The 1994 ECM can go. (Save it though, it's worth a couple bucks. It should have the 7427 PCM, which is a fairly sought after OBDI PCM)

The speedo requires a 40 PPM vssb signal. I'm not sure if the ford transmission has one. The diesel cluster requires a DRAC/VSSB to condition the signal. Fuel gauge runs directly of the fuel sender. Tach off the alternator windings. Oil pressure can run from a stand alone sender on the 12V. Ditto with the coolant temp gauge.

Cruise isn't going to work from a diesel since it is all done in the PCM. You can use the cruise off your 94 gasser since it is a a standalone module that uses a signal from the DRAC/VSSB. You'll have to "rig up" a bracket and a way to connect the cable to the throttle.

Wiring is going to be a mess. You'll have to sift through that and make it work somehow. Problem is, you're crossing gas/diesel, OBDI/OBDII years, the interior change years and even Ford/GM. It's do-able, but you are going to have to sit down with a couple different wiring diagrams, wire cutters and a soldering iron to make it work.

It's almost worth your while to just create a new wiring harness altogether.....

I would probably strip out the wiring harness completely and install a diesel harness. That would be the quickest way to get most of the wiring and components you would need to get the cluster up and running. Use a 95+ harness (preferably 96+ since 95 is a bit of an odd ball year) and the rest of the 95 interior bits will plug right in. You won't need the PCM from the diesel to run anything either. I'd probably grab the entire truck harness from a diesel actually. Closer all around to what you want since all the systems are pretty much stand alone. Instead of figuring out where to splice what, it's find which circuits you don't need and just strip them out.



Good luck, I don't envy you.

Did you read my first post? I said the truck originally has a 6.5 in it with the diesel cluster and wiring. I used the 94 wiring behind the 95 dash. I thought the 94 cluster would fit but i found out they are different. I was asking if the 95 6.5 cluster would work with the 94 harness. I don't have a pcm like I said above.