91 C1500 Cluster F**K

[Scooterwrench]

This all started with a non-functioning fuel gauge. I've got a 6 gauge set of aftermarket instruments and figured I'd put them to use on this truck. The fuel,temp,oil pressure,volt meter and tach are pretty straight forward. The VSSB on these are built into the cluster so not gonna work with my Marshalls. I bought a DRAC off evilbay and intend to use this to drive my speedo and cruise control. RWAL dump valve is shot so all that is getting sent to the landfill.
The DRAC has these terminals;
1,2,3 Not used
4 Cruise out @ 4,000 PPM
There is no 5 and 6 on these
7 VSS Lo in
8 Ground -
9 Ignition +
10 RWAL out @ 128,000 PPM (not gonna be used)
11 PCM out @ 2,000 PPM
12 VSS Hi in
13 Not used and no connection on the circuit board.
14 Not used
15 Speedo out @ 2,000 PPM

This is common knowledge for all you techno wizards and would be straight forward for me if it weren't for pin 13 possibly sending a 40 PPR to the PCM.

So my question is do I use pin 11 or pin 13 and if there is no internal connection on 13 then this DRAC is useless to me.
My PCM is 1227747, the broadcast code on the DRAC is QXJ

Thanks in advance!

 

[PlayingWithTBI]

So my question is do I use pin 11 or pin 13 and if there is no internal connection on 13 then this DRAC is useless to me.

I'm not sure but, I seem to remember 40 PPR is the same as 2000 PPM. Your VSS reluctor gear s/b 40 tooth. I'd try pin 11 but, as always, YMMV

 

[Scooterwrench]

I'm not sure but, I seem to remember 40 PPR is the same as 2000 PPM. Your VSS reluctor gear s/b 40 tooth. I'd try pin 11 but, as always, YMMV

I figured you'd be the one to know this. I haven't measured the circumference of my tires yet to determine my driveshaft speed,reckon I'd better do that today while I'm checking the rear brakes.

 

[Scooterwrench]

Well,it's definitely been an adventure.

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I was able to retain part of the circuit board for the connector,turn signal,check engine,brake and battery light sockets. I relocated the hi beam indicator and one of the illumination sockets that lights up the PRuNDL. I still have to wire in the DRAC which may wind up being downstream of the speedo. These speedos have an output so if it can't read the DRAC I can put the VSS directly to the speedo and wire the output to the DRAC for my cruise and PCM.

 

[PlayingWithTBI]

I still have to wire in the DRAC which may wind up being downstream of the speedo. These speedos have an output so if it can't read the DRAC I can put the VSS directly to the speedo and wire the output to the DRAC for my cruise and PCM.

IIRC my Dakota Digital dash takes the DRAC signal as well as the others. The neat thing is, my speedo is now programmable through the DD dash. AND, my EBL is programmable for PPMs so, I can change it with tires or rear end gears swaps.

With 275/60-15s I have this in my .bin, I'm +/- 2 MPH according to radar signs around town

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Yours may work similarly?

 

[someotherguy]

Nothing to add except nice work modifying the original cluster. Down with the moonies!

Richard

 

[Scooterwrench]

I've ordered a 7 position DIP switch to solder into the DRAC and plan to locate it under the steering column trim probably with velcro. If I need to change the output all I'll have to do is remove the two screws and drop the trim panel down and flip some switches,,,,,,,,,,,,,at least that's the plan.

 

[Moparmat2000]

Well,it's definitely been an adventure.

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I was able to retain part of the circuit board for the connector,turn signal,check engine,brake and battery light sockets. I relocated the hi beam indicator and one of the illumination sockets that lights up the PRuNDL. I still have to wire in the DRAC which may wind up being downstream of the speedo. These speedos have an output so if it can't read the DRAC I can put the VSS directly to the speedo and wire the output to the DRAC for my cruise and PCM.

That's a sweet looking setup. I did something similar for a V8 S-10 blazer a friend has. Those were all autometer Z series gages though.

 

[someotherguy]

I've ordered a 7 position DIP switch to solder into the DRAC and plan to locate it under the steering column trim probably with velcro. If I need to change the output all I'll have to do is remove the two screws and drop the trim panel down and flip some switches,,,,,,,,,,,,,at least that's the plan.

Depending on year model of drac it may have 2 banks of jumpers instead of 1, so you may wanna get a 2nd dip switch. The 2nd bank of jumpers is inverse of the first. Problem is, the dip switch package makes it just a little too large to use a pair of 7 position switches, you can carefully trim the edge of the switch package and use the tiniest amount of super glue to hold the package together at the corners. Otherwise, it'll fall apart. Example:

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Or one I did without shaving 7 position dips, just used 6 position instead, because the first position doesn't change in any of the settings on the tables. In this case I didn't bother flipping the switch package over, so you can ignore the numbers printed on the package, just consider their physical position on the circuit board:

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I have no idea why the forum software is rotating that pic.. but anyway.

Richard

 

[Scooterwrench]

Mine is the 1rst series with 7 pins. The guy advertised it as 90-92.