I have 2 1st Gen Cummins Dodge trucks I use on my farm. Both run and drive perfect. One is a 91 Non-Intercooled and the other is a 92 Intercooled. Both 4x4 and equipped the same.

Long story short, I am going to resto the 92 over Holidays and license it for the roads. It is rustfree and body straight except the roof line is totally eaten through with rust. It is not repairable. The 91 cab is rustfree and straight with a very nice interior and everything including the gauges work perfect and the rest of the body is totally beat up but rustfree.

I have decided to swap the 91 Non-Intercooled cab onto the 92. Obvious differences between the two are the cooling system, intercooler, 91 has an external voltage regulator and no ECM, the vacuum pump and power steering pump are different, and a few other minor things like the speedo wiring and no cruise on the 91.

The 91 drivetrain will be going into a Ramcharger later on after I get this truck on the road and finish my Crewcab conversion.

Before I get into this I would like to see if anyone has sorted out the differences between the wiring on the two trucks. I would like to go no ECM like the 91 and both trucks are 5 speeds. Any tips or ideas before I jump into this?

 

Your 91 has an ecm it is tucked in the fender behind the battery.

 

For sure there is no ECM there.

 

I think you meant '92, man.
A '91 Non-Intercooled only has the grid timer near the steering column, on the firewall.

If you're swapping cabs, check with your state's laws.
Most states require you to do a "rebuilder" or "assembled" title on them when any major component is swapped and you need either a title, or a junkyard receipt, to prove origin of the replacement parts.

You could also just do a roof cut and swap the roofs at the pillars.

Mark.

 

Thanks Mark,

The swap in Texas is not a big title issue.

I thought about doing a roof swap, but the interior is trash, windshield is fubar, and the dash is non-existing literally and the gauge pod is tied down to keep it from flopping around. Too many teenagers have had this truck airborn and the dash simply did not make it. Believe it or not, with all that abuse the kids gave it nothing else is wrong with the truck. All I have ever done to it in 5 years is change the oil and filters.

The cab from the 91 has an outstanding interior, everything works, and the dash and glass are perfect. Totally functional, presentable, and very clean unlike the 92. I would have no work to do at all on the 91 cab except the wiring to be sorted out. Quicker, easier swap than swapping rooflines overall taking into consideration no other work needs to be done except match the paint.

I guess I'll start out looking at the differences in wiring on the 91 and 92 trucks.

Anyone know of a complete write-up on deleting the ECM forever?

 

i did a swap using a 87 gasser cab onto my 89 diesel frame w/95 Ppump motor.i used a 92 gasser wiring harness under the dash & in cab in order to have power mirrors elec. windows/locks.i spent many many hours doing the wiring.i believe your easiest route would be to completly remove the under dash& hood from both trucks & just swap them to aviod countless hours trying to figuer out what goes where.

 

sorry about this 2nd reply,ran out of room.1 last thought ,i do believe the only real diff. between the 2 systems is that the 92 has the throttle position sensor & the 91 w/out od does not.chiltons does sell a repair man. that has some wiring diagrams that were helpful when i did my swap.hope this helps.goodluck.

 

You need to be careful when you switching parts especially the cab, the Vin number is in several place in addition to the tag in the window so you might need to register it as what the donor was.

If for some reason you were ever pulled over and they checked your vin plate they might get excited and think you have a stolen vehicle.

Also beware that posession of a Rosette Rivet in most states a felony.

I would at least check with your DMV first.

Dot't mean to marsh your mellow.

 

Jim, I'll go to the Texas DMV and check on this.

If I remember correctly in Texas the chassis title applies to the vehicle when a body is swapped.

 

There really shouldnt be that big of a difference. i would just put the 92 dash harness in the 91, but even then I don't think it's necessary at all?

If you're just doing a CAB swap, the 92 underhood harness should plug right into the 91 cab.

A buddy of mine did a 91.5 Cummins swap into a 90 ramcharger and his 91.5 underhood harness literally plugged right into the 90 ramcharger "cab" or firewall.

Can we see some inside pics of this 92 W250? I've never seen one of these dashes broken apart before lol

 

Crossy's, yes, I'll post some pics of the sad sight of the dash. Bottom line is that it is not there anymore, just the stuff underneath the dash. The glove box section came off first and then a crack right down the middle of it started and the whole thing broke apart gradually.

 

I got an answer via the Texas DMV today on this. I will have to take the truck in to get it inspected, get an inspection certificate, and then the DMV will re-title it.

 

Take it from me, '91 and '92 ARE different.
In short the Hazards won't work and there was something else that I can't remember that wouldn't work when swapping between '91 and '92.

It doesn't matter if it's intercooled (ECM behind the battery) or not, either.

'92 and '93 are direct plug in, engine harness to dash.

Either '91 harness will also work in a '90, but '89 is it's own critter.

Mark.

 

why don't you just swap the beds

 

Bottom line is that the bed and front clip on the 92 are excellent. The problem is that the roof rot has destroyed the cab. The body on the 91 is very, very rough except for the cab. That is why the 91 is going on the 92.