1990 electric instrument cluster/speedo

[crossy]

Was the electric speedometer only used on the 90-91 models ???? I know it has nothing to do with the fuel injection- so to speak anyway- because the GM trucks have been injecte since 1987 and I KNOW that the 87 and 88's's did not use this type of speedo.
What was the real reason for using it. thanx ,crossy

[ARAMP1]

I have a 90 and it has a cable speedo.

[edman87]

a change to the transfer case or trans from gear drive speedo to electronic. In 90 the t-case changed from a np208 to a np241. I didn't know there were any 90 models with a cable speedo, yours must be a 2wd sub or a very early 90.

[ARAMP1]

Originally Posted by edman87

a change to the transfer case or trans from gear drive speedo to electronic. In 90 the t-case changed from a np208 to a np241. I didn't know there were any 90 models with a cable speedo, yours must be a 2wd sub or a very early 90.

It's a crew cab with an NP205. That may have something to do with it since the door tag says 05/90 for the date.

[edman87]

That would be the reason, I always forger that the crew cabs ran a few extra years and had lots of differences.

[crossy]

SO basically Gm did a Dodge/ Ford thing where it split half year -doohh
anyway thats what I thought , thanx, crossy

[special-K]

I think the manual trans models had a cable speedo.
Was the 4L80E used in all automatic 90/91s?Or,just the HD applications?Would a Blazer or 1/2t Suburban have a 4L80E,$L60E,or 700r4?And,did they all have NP241s?I have a`90 4spd manual Blazer and a`91 4wd 2500 Suburban w/4L80E and both have the NP241.

[edman87]

np241 first year was 90, hence the elec speedo. Also a 4l80 would need elec speedo. I didn't know a 4l80 was available in 91. 700r4 was only auto in blazers that late from what I understand. I have a 89 k5 700r4-np208, only year for a mech speedo with trip odo other than some 88's. I have heard rumors of a 5 speed in 89-91 blazers, but neter confirmed.

[wildmanaaron]

Can someone post a picture of the electric speedometer (PLEASE!!!) and maybe tell what it came out of if possible. I would like to see how it looked on the front and back. I am trying to get everything in order for a LT-1 or LS-1 swap and having a speedometer with an electronic hookup would save me over $500 by not having to have the transmission tailshaft modified for using a cable-driven speedometer.

[crossy]

as you can see from the front view there is no difference but from the back there is no cable connection. the speedo gets its feed from #18 track on the 18 point connector. there are three feeds but two are just common. probably wouldn't be that tough to figure out how to re-arrange the connectors from a typical 81-89. I've rearranged a few it just takes alittle time. you could rearrangeand have the #18 track open and then add that wire'stand alone' into the system. where exactly that wire goes to down below your truck i have no idea. prolly NOT right into the tailshaft of the tranny. prolly into the ECM first ?????????? ,crossy

[wildmanaaron]

Man, event the printed circuit looks different on that cluster.

I think there is a salvage yard close to where I am at school at. I just bought a tach dash set-up with the correct style gauges for my 1981 Blazer too. I wonder how hard it would be to use that cluster with the electric speedometer?

[crossy]

yeah the PC has to be different. the one I show a picture of can be bought off me for around . but this isn't a classifieds forum. would trade for any year tach dash.

[wildmanaaron]

I think I'm going to keep my tach dash for my 1981. I do have one with the earlier style indicator fonts that I will be selling soon.

I would like to see one of those clusters in person to see what all the difference is on the gauges.

[wildmanaaron]

Crossy,

Man you got me excited after learning about a 73+ cluster that has the speedometer electronically driven. Like wanting a new toy when you were a kid, I had to learn more about this for my FUEL INJECTION SWAP/ELECTRONIC TRANSMISSION SWAP.

I went to the local CHEVY dealer and asked a mechanic to see what he had in the ALLDATA or MOTORALLDATA computer. Well they had plenty. I will post the wiring schematic for the #18 wire. It goes from the plug from the back of the cluster, to a "Digital Ratio Adaptor Controller" where it terminates. The rest of the wires on this controller go out to the ignition 12 VOLT, vss input, and VSS to ECM signal.

What are you trying to wire up with the electronic cluster?

http://www.studentweb.eku.edu/aaron_cowan4/img004.JPG

[Jonboy]

The DRAC is a white box, under the raiio area.

[wildmanaaron]

Anybody ever seen one of these style clusters with a Tach. I am needing the printed circuit and possibly the greenish cluster piece to use a tach in the electric speedometer cluster I just bought.

I called GM and they do not show this model cluster ever having been equipped with a Tachometer before??

[crossy]

we all looked int othis before. the parts books I have don't even show it after 1981 . in the early days i swore there was no tach after 81 for that reason . if you were lucky enough that you had a salesman that knew RPO codes he could just check the box for U16 or whatever it was and it would come through. since the basic layout and design of the font was the same since 1980 it wasn't really a big deal, but your electric cluster uses a whole different PC on the back. before we could try to reference big truck, like C60's, to get different combos but i doubt any of the big trucks ever came with electric speedos because one thing they were never stupid enough to try was to put a 700R4 in big trucks. I'm not saying this cant be pulled off but I bet you need to check into the streetrod world to get a buffer or conversion somewhere. crossy

[edman87]

Anybody got the lowdown on a camaro tach install? Seen it somewhere before, maybe here.

[wildmanaaron]

I just wonder if you could wire up the electric speedometer straight into that little plug on the side of the housing with the necessary wires, and somehow use the "older" Tach cluster I have, meaning stick the electric speedometer into the older dash, but use wiring to wire it up straight out to the required terminals.

RUSSEL seems to know a little about this. This was partially his idea too!

[edman87]

I don't see why you couldn't wire old and new together if you know what is what.
It has been a while since I saw a pic of the camaro tach in truck cluster, but I remember it being rather stock looking and it has a higher rpm range.
I will see what I can find out about it, thinking of doing that later on any way.
Was 89 the only year for a trip odo in a cable drive unit? I have one here and was thinking of trying it out in my 87k5. The trip reset is stuck, but should free up easily.

[Jonboy]

I think there was one in '88 also, and the font is the same as the 80-up gauges. They added a lot more hash marks in '89.

[1976K5CHALET]

Basically a 90-91 only speedo cluster....as i see now early 90's didn't get the goods. And for the ultra rare...rpo 8A8....in with tach flavor...still have yet to lay hands on one but i am still looking for one just like the 90-91 only power mirror harness i want so bad...genuine hend teeth.

The speedo recieved its signal from the drac...digital ratio adapter...and both ethe drac and the speedo can not be had thru gm....i tried...gm somewhere in the late 80's got squatted on by the gov about selling speedo's without having things properly recorded so they quit selling them...at least thats the story i was told by my local parts man this year. If you need one repaired or a drac...ISS (instrument sales and service can take care of things for you) i think the last drac i bought burned for our burb's gear ratio and tires size was 85 bux to the door. The drac had 4 outputs depending on how the truck was optioned....A) ecm B) speedo C) cruise servo D) abs ecm.

Pretty simple system to work around. If you have a speedo cable order a 2 pulse vss from Howell and run the signal in to a stand alone drac to convert the analog signal to digital the ecm can use...along with all the other goodies....and i see you found the post on how to make the drac programmable with a simple dip switch like that used in a standard over the road semi speedo head...

Sorry i have disappeared for so long but i have been stuck in canada since the end of july training in the field on some different em mwd tools the company uses up here. I did make it home one time for a few days for my daughters bday in sept and managed to buy a new truck on my way thru casper wyoming. Got almost 6k on the clock already....but i love the power of that new duramax....she's an 06 2500 HD 4x5 crew cab with the 6.5 box and a www.vanworks.com H4 package...i added dvd headrests for the kids...spray in liner...and a are locking hard cover on the bed for my oilfield gear.

Oh yes...i forgot....must have something to do with just driving 500 miles to regina sk in a snow storm....anyways the 4L80E was standard in 91 only Burbs and Crews....just had to buy either a C20 or a K20-30 to get it. I borrowed an ecm and complete bumper to bumper harness from a wrecked 91 C20 Burb in the local bone yard early this year....the owner of the yard swears the trans is a TH400 by his books so since i have been gone 5 moths or so...gonna swing in next month and see if its still a th400...if so its going home with me...


DW

[wildmanaaron]

I plan to wire the speedomter up directly to an aftermarket LS-1 harness. The three prongs on the speedometer are for a ground, power, and the VSS input.

RUSSEL suggested looking at the clip used to attach to the Green Box behind another 1987 Chevy Truck cluster I have. I looked at that clip and it doesn't line up exactly.

[wildmanaaron]

Here is an electric speedometer cluster on eBay:

http://cgi.ebay.com/ebaymotors/81-87...QQcmdZViewItem

[wildmanaaron]

TTT-Anything new on this subject??