Factory tach in a 87' cluster

[_SLACKER_]

Whats up guys, I have a question! has anyone tried to put a factory tach in a 87-91 cluster? the reason I ask is because I had my 90' k5's cluster out recently replacing the bulbs and I noticed that there is a "BOX" behind the speedometer that I think is for the cruise control and don't know if this will effect the operation of anything. Thanks for any input and sorry if this post is in the wrong place.

[87Bob]

Originally Posted by _SLACKER_

Whats up guys, I have a question! has anyone tried to put a factory tach in a 87-91 cluster? the reason I ask is because I had my 90' k5's cluster out recently replacing the bulbs and I noticed that there is a "BOX" behind the speedometer that I think is for the cruise control and don't know if this will effect the operation of anything. Thanks for any input and sorry if this post is in the wrong place.

I will find an answer to this before to long. Last winter I added a Tach cluster to my 85. Since then I have found a Cruise unit I plan to add this winter. That means that "A" I will have to move the Tach to my old cluster(because I know the spedo has the window and spinning bar for the cruise. Or "B" I will have to move my old speedo to the currenty cluster because it doesn't have the corect connections for the cruise. Or "C" I'll get lucky and I can just mount the cruise to the current cluster because it has all the mounting tabs I need for both the cruise and the tach. I'll take a look at the old gages and see if they have what is needed for the Tach today when I get out to the pole barn and let you know.

[b454rat]

I put a factory tach in my old 87. I think I used the 87 cluster, cut a small hole in the back for the wires to go thru. Truck didn't have cruise, but had cable speedo with the VSS off the back. Worked great, kick myself in the ass for selling it with the truck....

[Keith Seymore]

Originally Posted by b454rat

I put a factory tach in my old 87. I think I used the 87 cluster, cut a small hole in the back for the wires to go thru. Truck didn't have cruise, but had cable speedo with the VSS off the back. Worked great, kick myself in the ass for selling it with the truck....

That's what mine has. Factory tach with cruise; I'm guessing all of the cluster housings (the blue plastic part) have the window for the cruise sensor, because we would not want to proliferate housings to cover all the different speedo/gage/no gage/ combinations.

K

[87Bob]

Originally Posted by Keith Seymore

That's what mine has. Factory tach with cruise; I'm guessing all of the cluster housings (the blue plastic part) have the window for the cruise sensor, because we would not want to proliferate housings to cover all the different speedo/gage/no gage/ combinations.

K

Hi Keith glad you were looking in on this thread. I don't know what year the tach equiped cluster I have is from, I bought it at a swap meet. Do you remember how far back the cruise control went that had the head unit on the back of the speedo? I'd like to be able to just add the cruise unit to the one currently installed as I had a gage repair shop go through it. I checked the two cluster cases I have and neither would accept the Tach without some mods. They don't have holes for the blades on the wire connector to stick through. Also the printed circut would need to be switched as the orginal has no cut out for the wire connector for the Tach.

[glock35ipsc]

Originally Posted by _SLACKER_

Whats up guys, I have a question! has anyone tried to put a factory tach in a 87-91 cluster? the reason I ask is because I had my 90' k5's cluster out recently replacing the bulbs and I noticed that there is a "BOX" behind the speedometer that I think is for the cruise control and don't know if this will effect the operation of anything. Thanks for any input and sorry if this post is in the wrong place.

The 90-91 speedo will be electronic, not cable driven like an 87 and < truck and 89 and < Blazer/Burb would be. That is probably the "box" you are seeing behind the 90 speedo.

91 Blazer electric speedo:

[_SLACKER_]

Glock,
yes this is what the clusters I have look like. Is the tach a separate unit IE it doesn't have to be installed in the cluster housing to work? all it needs is power and ground and input from the distributor rite? it seems if this is the case and looking at you picture of the back of the housing that small square on the upper left would a good place to cut for the tach connector. and just get a new circuit board for the small fuel gauge.

[clinebarger]

Its a speed signal buffer. the dashes with a mechanical drive and TBI or feedback carb have a built in speed signal buffer the all electric dashes have a remote mounted one

[_SLACKER_]

clinebarger I don't think I'm understanding what your saying.

[clinebarger]

The Vehicle Speed Sensor (VSS) Buffer is a solid-state device that is used to change the signal from the speed sensor to a digital signal. The VSS buffer will change the signal from the speed sensor to a signal containing 4000 pulses per mile for the instrument cluster.

The VSS buffer is matched to the final drive and tire size of each vehicle. It must be replaced with the proper buffer to match the final drive and tire size of that vehicle.

CAUTION: If the final drive or tire size is changed for any reason, the buffer must also be changed to continue to produce an accurate speedometer/odometer reading. The incorrect buffer will also affect the anti-lock brakes, engine control module, and cruise control module.