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Ok, read all kinds of threads on the drac and a 241, couldnt find what i need

J

Jodean

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Ya, newb

was sent here as a search for my problem. Site is great, looks like alot of good info.

Heres my issue.

Bearing went out of my 208, go figure, it would leak oil out the rear seal like crazy if i tried to power brake (thats how we found out what was leaking so bad)

So i yanked it out, the guy that rebuilt my 700 gave me a 241, but it has electric speed sensor

What i want to do, i now know it is possible, is use the electric 241 output, pull my mech speedo, install a 90 sub speedo and drac.

What i need to know now, before i go out to the ewe-pull yard in sub freezing weather, where is the drac on a sub?

Then im diesel, so all i want is a speedo. What wires do i hook up to what? Thats about the only thing i cant find, i saw the drac "expert" threads but some of his links were down.

Would it be possible to rig up cruise onto my 6.5 using the 90 sub cruise setup along with this new drac?

What? no signature?
86 K10 6.5td 700r4 241 39" Baja Belted 1 ton axles
 
well theres the 3 things needed for a speedo.

the speedo, the drac, the unit in the tcase.

the drac is what you can pin out to change your speedo reading. In the 88-98 trucks i believe they were in the glove compartment area.
 
no, only used on electronic speedos....mainly 89 and newer
 
The DRAC module usually lives quite close to the ECM which is located just behind the glove box door on these trucks.

Hooking it up is easy as pie as well, it does not care if you have a diesel engine, and it will operate your cruise control without any trouble. I've attached a pin-out for the DRAC module for your reference, but will quickly describe the circuit anyways.

Of course, the DRAC requires it's own power source, and must be connected to an ignition power supply and a ground. The tone ring sensor is not polarity sensitive, so you may connect the two VSS wire connections to either pin on the DRAC. The 4000 pulse per mile connection is wired to your speedometer's input pin on the instrument cluster, and the cluster itself provides a 12V ignition source and ground to the speedometer. The 2000 pulse per mile connection is wired to your cruise control input pin which will have been previously connected to the green optical speed sensor you'll be removing with your old instrument cluster. I do believe that the wire you are looking for in that case is yellow in color.

The DRAC does produce signals on a few other pins for the ABS (14 000 pulses per mile plus change), and for the ECM (also a 2000 pulse per mile signal) but I have not included them on the pinout to simplify things.

Also, keep in mind that you will NOT be able to simply plug the new electric cluster into your truck. You will need to re-pin it from the top down or risk burning gauges up or starting electrical fires. This is not a hard procedure, and can be done if you take note of what wires operate which devices on your old cluster before pulling the pins out of their stock locations on the connector. The new cluster will be easy to trace, and it is simply a matter of knowing what each wire you have removed did on the old cluster and connecting them in the same way on the new one. You'll wind up with a couple extra ignition power wires (which are pink / black) and ground wires, but everything else should be re-connected to the new cluster. The only difference between your old diesel cluster and the new gasoline electric cluster is in the oil pressure gauge (which is 0 - 80 PSI for a diesel, and 0 - 60 PSI for a gasoline engine) but you can simply swap your 80 PSI gauge in and it will operate just like it did before. The fuel gauges are the same, but if you wish to retain the DIESEL ONLY silk-screening, you can again just swap the gauges out without any concerns.

Finally, you may want to look into installing a set of DIP switches on your DRAC before installing it in your truck so you can easily calibrate it for gearing or tire size changes. Here is a link to an excellent tutorial for calibration: http://www.tbichips.com/drac/

This is well worth the effort to switch over to. Eliminating that noisy, often unreliable and inaccurate cable drive is a very nice thing! I had a 90 Burb cluster in my old 1980 GMC K25, and now in my 1985 K5 Jimmy

DRAC.JPG
 
ok that all makes sense, i do have a gas cluster now, i removed the small gauges and installed all mech gauges back there, that part of the cluster is cut out, all i have left is the speedo and fuel gauge which i plan to just wire up without the circuit board stuff at all.

apparrently i cant open your picture.....do i have to be a supporting member? seems i cant do alot of things on the forum.

do you have an alternate picture like at photobucket? Im hoping for the pin out like 12v goes here, ground is here.....type diagram for the actual power source to the drac and what sensor wire goes where.
 
The DRAC in my 91 Suburban was under the driver's side dash kind of between the steering column and the radio. It is a white plastic encloser.

On the conversion part, sorry, I can't help.
 
cuervo said:
The DRAC in my 91 Suburban was under the driver's side dash kind of between the steering column and the radio. It is a white plastic encloser.

On the conversion part, sorry, I can't help.
Click to expand...

Isnt that what you did on your 80?
 
Sorry, I always forget about the subscription bit, I uploaded the image to my server for you:

drac.jpg


I took my DRAC out of a 88+ new body style truck, if someone mentioned that the DRAC is by the steering column, take his advice over mine in that respect.
 
cool, thank you!!

hope to get some parts together for this, seems pretty simple now

Ill post the result when i get it figured out
 
ok thanks guys for the info,

now i finally made it to ewe pull to get a speedo......i guess i found out more stuff now.....

My plan was just to use the electric speedo and wire it up in my current cluster......guess you cant do that as the speedo is plugged into the vinyl circuit board setup on back of the cluster, and i did not grab the cluster pigtail.......crap!

So i have to swap the entire cluster? then figure out what wire feeds what to the circuit board.......i already have all the small gauges replaced with autometer, so if i have to swap clusters ill have to butcher that one up too i guess,

I was really hoping the speedo just had a ground, power, and sensor wire like an aftermarket one would have......wastn prepared for this much work and now i think i have to go back to ewe pull and get that pigtail i guess.

Is this the way to do it??
 
Yeah, I was a bit surprised by that same fact when I first did my speedometer swap too. I wanted to swap it into a factory tach cluster I've got, but wound up just re-pinning my instrument cluster connector and swapping a few gauges around to suit my needs (diesel engine).

Re-pinning isn't too terribly much work though, es specially if you are only wiring in an ignition supply, ground and signal from the DRAC to the speedometer.
 
so you used the newer cluster then? the one the electric speedo came in?
 
Yup! The reason why I didn't install the tach is because the location of the small fuel gauge is used by a couple of idiot lights on the newer cluster. I need to find and install a medium duty tachometer which has the fuel gauge integrated with it to avoid that problem.
 
Russell said:
The DRAC module usually lives quite close to the ECM which is located just behind the glove box door on these trucks.

Hooking it up is easy as pie as well, it does not care if you have a diesel engine, and it will operate your cruise control without any trouble. I've attached a pin-out for the DRAC module for your reference, but will quickly describe the circuit anyways.

Of course, the DRAC requires it's own power source, and must be connected to an ignition power supply and a ground. The tone ring sensor is not polarity sensitive, so you may connect the two VSS wire connections to either pin on the DRAC. The 4000 pulse per mile connection is wired to your speedometer's input pin on the instrument cluster, and the cluster itself provides a 12V ignition source and ground to the speedometer. The 2000 pulse per mile connection is wired to your cruise control input pin which will have been previously connected to the green optical speed sensor you'll be removing with your old instrument cluster. I do believe that the wire you are looking for in that case is yellow in color.

The DRAC does produce signals on a few other pins for the ABS (14 000 pulses per mile plus change), and for the ECM (also a 2000 pulse per mile signal) but I have not included them on the pinout to simplify things.

Also, keep in mind that you will NOT be able to simply plug the new electric cluster into your truck. You will need to re-pin it from the top down or risk burning gauges up or starting electrical fires. This is not a hard procedure, and can be done if you take note of what wires operate which devices on your old cluster before pulling the pins out of their stock locations on the connector. The new cluster will be easy to trace, and it is simply a matter of knowing what each wire you have removed did on the old cluster and connecting them in the same way on the new one. You'll wind up with a couple extra ignition power wires (which are pink / black) and ground wires, but everything else should be re-connected to the new cluster. The only difference between your old diesel cluster and the new gasoline electric cluster is in the oil pressure gauge (which is 0 - 80 PSI for a diesel, and 0 - 60 PSI for a gasoline engine) but you can simply swap your 80 PSI gauge in and it will operate just like it did before. The fuel gauges are the same, but if you wish to retain the DIESEL ONLY silk-screening, you can again just swap the gauges out without any concerns.

Finally, you may want to look into installing a set of DIP switches on your DRAC before installing it in your truck so you can easily calibrate it for gearing or tire size changes. Here is a link to an excellent tutorial for calibration: http://www.tbichips.com/drac/

This is well worth the effort to switch over to. Eliminating that noisy, often unreliable and inaccurate cable drive is a very nice thing! I had a 90 Burb cluster in my old 1980 GMC K25, and now in my 1985 K5 Jimmy
Click to expand...

Russell.....this is good info, thanks. You did mention that you left out the connections for the computer to simplify the drawing. Do you happen to know where the rest of the wires go if I want to use my 89' ECM? Will it also be 2000 pulses to keep the ECM happy?

I actually picked up 2 instrument clusters from 2-1990 Blazers and the T-case housing along with a tone ring. I also picked up a DRAC from an 1990 Suburban. Mine is gas so I'm hoping the pins on the back are similar.....but I will investigate before installing anything.

Thanks!
 
The ECM wants a 2000 ppm signal input on A10 (brown wire). I do have a revised drawing for you though because I have the cruise control hooked up where the ECM normally gets it's signal from in the drawing above and I messed up the ignition wire location (doh!)

Please see the attached drawing!

DRAC.JPG
 
Thanks Russ for the clarification on that and it looks like the ECM and cruise could actually be interchangeable but good to know. On the DRAC I got, I actually have a blank spot, then the speedo pulse, a blank and then the VSS wire. Interesting enough, the VSS wires are the identical colors as the one I pulled from the 1990 Blazer.

I have not looked yet, but would the lead going to my 89' ECM be tied to the green cruise control box?
 
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