freight train

Hi guys, I have always wanted a cummins ramcharger. I just went and picked up my donor (1990 W250, 5spd,) and already have my RC. I dont plan to start the actual conversion until next spring so I can save up some needed cash to buy the needed parts. I bought a set of 3.07's axles about 3yrs ago with this build in mind. So I plan to rebuild them and instal a Limited-slip in the rear. I want 3.07's since I plan to use this RC as a DD.
I already bought a 93 fuel sending unit to intall into my RC's tank. I plan to install a new clutch kit (Sachs) when I do the build. Thats just one thing I want to save for. And with Christmas around the corner and the fact I spent $2k for the donor I need to watch my pennies.

Anyways, I am asking this to you guys that have made this swap or atleast used a non I/C motor in a 91-93 RC. Can I simply undo my big bulkhead connector when I pull both motors and install the one from the 90 into my ramchargers firewall plug? I know I will have to change the dash info center but the interior harnesses should be the same except my RC has ac and intermitten wipers which the donor truck does not. I could care less about the ac but I dont want to burn up anything. I already bought a harness that that goes back from the firewall back to the fuel tank from a cummins first gen. I want to use the donors (90) engine harness to utilize the no PCM to make it simple. I know there is a lot to this swap. I just thought I would ask some of you guys what you ran into in doing the swap? Use your trials and tribulations to help me. Any helpful advice is greatly appreciated. Here is my starting point.

freight train

C mon guys. I know some of you out there have done this conversion. What wiring issues did you run into? I know what I need to do for the fuel. But as of right now I am kind of lost on the wiring. Firewall out. Can I use the 90's harness on the 92's bulkhead connector? Thanks for any help.

PapeCAT

I did my conversion into a '72 and used the '72 harness with a 1991.0 Engine.

The member on here with the white '93 ramcharger, Fred Swanson. I'd read that one for sure if you haven't already FYI.

https://www.dieseltruckresource.com/...d.php?t=199598

Nice pair of Dodges BTW! Matching red just like Fred's matching White rigs.

freight train

^Thank you Cat.

My dad got me hooked on reds.

thrashingcows

If you want all the "Wait to start", "Low fuel", "water in fuel" etc from the on board diagnostic center then you'll need to swap the entire wiring from the donor truck into your RC. If you don't care about that then just drop your motor in, hook a 12V ignition source to your FSS and your good to go.

You will not have any grid heaters, or KSB control though. Not that big a job to swap everything over. Just use masking tape to label all your plugs and ends and you should be good to go.

freight train

I do want the info center stuff. I know the donor truck is a base model. What about the intermitten wipers and the differences in plugs from the 90 (diesel) harness to the 92's rc harnesses. I know the RC has a light in the headliner where the diesel should have a light in the dash. Im sure it wont be to much trouble to swap the complete harness from the 90 to the 92. I know the 90 utilizes a voltage regulator to charge the battery. Any known issues swapping the 90's complete harness into the later RC's body? Thanks Cows, I see you have done a similar swap. Your advice is appreciated. I was hoping it would be as easy as undoing one firewall connector and plugging in the diesels. Then changing the info center and fuel tank/rear light harness to the diesels. I already have a 92 diesel tank unit for the return line. Thank you, again

thrashingcows

The actual wiring swap should go fairly easy. Just remember to label everything. As for the dome lamp, the truck should have a dome light, or cargo light set-up, so that should be the same, or darn close to it, hook up as the RC'ers.

Most of the optional equipment was all pre-wired into the factory harnesses, so then they only had to produce one harness for almost all applications. So depending on what options you chose they would then plug those into the existing harness. I would suspect that the intermittent wipers will plug in fine.

Only other thing I can think of off the top of my head is that you might need to swap the steering column as well. Depending on what your RC has on the column, and the 90 has. Mainly thinking of the high/low beam switch and the delay wipers.

I'll try and keep an eye on your progress and help if I can.

freight train

Man I didnt even think of the wipers. I know the high/lows are on the turn signal like my 92 but am not sure about the wipers. I am trying to buy a Dodge service manual for the 90. That way I will have a schematic on its wiring. Thanks for the help.

oliver foster

My '85 crew has the floor switch for the headlight high/lows removed and instead use the tilt steering coulmn from the '90 LE Cummins, with the controls on it. It all works other than I haven't gotten cruise to work yet.
The wiring was swapped on both sides of the firewall to the '90 wiring.
I love the R/Cs have a fun swap.
Nice find on 5-speed donor truck as I knew you where looking for 5-speed for a while.
I will be putting a 5-speed in my crew when I get some free time.

freight train

Thanks Oliver for the nice words. This is why I love this site. We all have one common love.

Guys here is a question I thought of today and want to run it by you swapping veterans.

What if I found a 1992-93 Engine harness and PCM. Then installed a tach sensor on my non i/c motor? Could I use them all together (I know I might have to make the engine harness work with my motor) and use my factory underdash harness? I am pretty sure all RC,D,and W's use the same dash harness from 1992 to 93. What would be involved in putting a tach sensor on my 90 motor? Would I need a new front engine cover? I dont know if my 90 engine has provisions for the sensor. Im sure people have done it. My way of thinking is it would be easier to install the sensor, I already have a 5spd PCM, diesel info center, and probably could find a 92-93 engine harness. And that would be easier than tracing wiring gremlins. Anyways, thank you to all for your helpful info. I like to know what I am in store for before I am head over heals. Robert

freight train

Guys looking in my parts book. The underdash harnesses are different between the ramcharger and a diesel. So I will have to swap out the dash harness in the RC with one from a diesel. I still want to use one from a 92/93 and put a tach sensor on my 90 motor. Then I can use a 92/93 engine harness/PCM and make it look and run factory. Robert

SmokinJDGMC

Hey robert
this is your Ebay ECM guy!

You will also need the intake plate with the Two sensors in them!
I have a complete under the hood wiring harness and plate with sensors if you need them! I also have the wiring adaptor that hooks up to the alternater.

Your project will be a nice one when completed.
Too bad your not a little closer! WV is along ways from SW Idaho!

Larry

Mark Nixon

Plan on losing the heated backglass on the R/C, regardless of which diesel harness you use.
You'll also need to modify the harness a bit for the R/C's domelamp set-up.

You'll need to use the steering column from the donor truck, as well.
The low pressure switch for the '90 uses a different plug than the '92, as well as it's located differently due to the port valve's location (frame rail vs. below the booster).

When I did my '92 DAMNCHARGER, I used everything I could related to the the '92-'93 Model years.
Fortunately I ended up with basically new engine, dash, and transmission wiring harnesses.

TIP: Use a '91-'93 Fuel tank sender assembly from a diesel and rotate the basket assembly 180*, so that the float and wire assembly points AWAY from the from wall of the R/C's fuel tank.

For me, it was, all in all, a very straightforward swap.

Mark.

BHD

Freight Train. I am watching this post and plan to get my RC swap done as soon as they make a 30hr day. Actually found a 518, and a bunch of tranny pieces for my swap since the donor's juice box is smoked. I planned to swap entire harnesses from the donor rig, just to make things easy.

freight train

Thanks Mark,
I just purchased a complete wiring setup from a 92. Dash, underhood, and engine harness for a 4x4/5spd. I figured to loose the rear defroster. I already purchased a 92/93 diesel complete fuel sending unit. I found a guy who is selling me the complete crank sensor/ with all its mounting and a air intake plate with the two sensors in it. My plan right now is to swap in using as much of the 92/93 harnesses and such as possible. That will allow me to use the RC's steering column. I have a spare I/C and all the piping,clamps, and rubber joints. I just havent decided to i/c it or not. If its just a matter of cutting two holes into the rad support than I will probably go for it. I want to find a 92/93 H1C if I do.

BHD, keep me posted on your build. I wish my RC was as clean as yours!

Guys I tore down my D70 sun and ordered a power locker for it. Cost $670 shipped. Expensive using the older D70 with 35 splined axles. But the 3.07's will make up the difference. I hope to have it by next week. Coming from Randy's ring and pinion. West coast.