does any one know the pule input for the 88-up dashes ? thanks. i swaped a 4l80-e in to a 88 pickup and want to hook up the speedo . the wire harness is a stand alone unit as thay didnt offer 4l80-e yet.
CK5
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speedo input in dash for 88-up trucks
- Thread starter sweetk30
- Start date
come on now no one knows?
All we know are the '87-91 C/K/R/V setups! 
Seriously, that was before the electric speedos in the R/V, so I can only guess what GM was using. Electric speedo's were available in just about every GM vehicle in the late 80's, except our trucks. The typical pulse outputs were 2000 or 4000 per mile, and without looking at the DRAC info, I think the '90-91 R/V clusters were 4000PPM.
What does the '88 use to drive the speedo? (DRAC, VSSB, etc) I'd assume DRAC, but that's all I can do, assume. If it's the standard 2000 or 4000, the DRAC can be used with that dash and the 4L80E, and the pinouts are known for it. If you can work backwards (wire from speedo goes to terminal X on DRAC for instance) then you'll know what it requires. A factory wiring chart should show the speedo wire.
Seriously, that was before the electric speedos in the R/V, so I can only guess what GM was using. Electric speedo's were available in just about every GM vehicle in the late 80's, except our trucks. The typical pulse outputs were 2000 or 4000 per mile, and without looking at the DRAC info, I think the '90-91 R/V clusters were 4000PPM.
What does the '88 use to drive the speedo? (DRAC, VSSB, etc) I'd assume DRAC, but that's all I can do, assume. If it's the standard 2000 or 4000, the DRAC can be used with that dash and the 4L80E, and the pinouts are known for it. If you can work backwards (wire from speedo goes to terminal X on DRAC for instance) then you'll know what it requires. A factory wiring chart should show the speedo wire.
dyeager535 said:All we know are the '87-91 C/K/R/V setups!
ah no we do all others also.
just was thinking someone might have tryed this and would know. thanks for the info.
4l80e is a bit of an interesting animal... It apparantly has two speed sensors. One for input speed, and one for the output speed. However, I am having a heck of a time trying to figure out how many pulses per mile, per driveshaft revolution or whatever it is suppost to be.
I am gonna go on a limb and assume it is the same as a 4l60e or a later 700r4 and say it is a 40 pulse per driveshaft revolution output speed sensor... If that is the case, then it should pretty much be a hook the wires up and go type thing, as your 88's original 700r4 will have had a 40 pulse per driveshaft revolution ouptput as well...
I am gonna go on a limb and assume it is the same as a 4l60e or a later 700r4 and say it is a 40 pulse per driveshaft revolution output speed sensor... If that is the case, then it should pretty much be a hook the wires up and go type thing, as your 88's original 700r4 will have had a 40 pulse per driveshaft revolution ouptput as well...
Since the 205 I pulled out of a 1991 V3500 had the 4L80E in front of it, I can at least confirm that in that application, the OUTPUT was 40PPR at the output shaft. A 2wd would have been the same.
I believe if you go over the VSS section at jagsthatrun, you'll see there were only about 4 different setups for VSS.
I believe if you go over the VSS section at jagsthatrun, you'll see there were only about 4 different setups for VSS.
