Convert your Turbo Regal gauges over to late model Buick LeSabre gauges!

 

This page shows how I installed a late model Buick gauge cluster in my 1987 Buick Turbo Regal. The factory gauge cluster was very bad with only a large rectangular speedometer, a fuel gauge and a LED bar graph tach and boost gauge. VERY BORING for such a high performance car. Please note that this is a very generic description of how to do the job. Some of the steps are not shown all and will be assumed you will know how to get around those steps to get these installed.

 


 

 


Below are the list of parts that I used to create this conversion. Not all steps or details are covered since custom fabrication is always time consuming. Remember to test fit the part many, many times so it will come out looking great and so you won't screw up too much. So, lets get started!



This is what you'll need.

1. Gauge cluster along with 8" of the harness plug from a 92-93 LeSabre.
2. The "information center" that is located on top of the dash (same car).
3. 4 wire oil pressure sender with harness connector (same car)
4. 3 wire temperature sender/sensor with harness connector (same car)
5. Light green speed sensor buffer with connectors from a mid 80's GM car.
6. Speedometer head from a early to mid 80s GM car.
7. Three "C1" Cluster harness connector terminals from a bone yard or new ones.
8. Small piece of 1/4" Plexiglas about 2"x3" or other material for fabricating a speed sensor mount.
9. 470 Ohm resistor from Radio Shack or the one from your original alternator light bulb socket. I'd just go buy one and save your original.
10. Brown wire, Green wire and white wire or just any colored wire you choose. Color coded salvage yard wires will work too!
11. Caspers Electronics C1 harness adaptor.
Misc...
Soldering gun, additional color coded wires, heat shrink wrap, 3 idiot lights bulbs & sockets for the BRAKE, CRUISE and FASTEN BELT lights and some sort of adhesive like JB Weld or "hot glue".

 

 

 

Lets begin!


Remove the original clear lense from the LeSabre cluster. Keep the black spacer because you will still be using that in the end.
Place the lense onto a piece of thin Plexiglas and mark where the mounting holes need to be drilled and drill them out. This will be the protective lense for the cluster as you work on it and will be used on the final assembly. This should be an easy task if you are attempting to do this conversion so I won't be going into details on this part.

 


YOUR ORIGINAL CLUSTER MOUNT and BEZEL WILL HAVE TO BE CUT! If you want to save your originals then you'll need to get some more from a donor car. Sooo...
You will need to remove your inner gauge cluster mount from your dash or pick up one from another Regal.









 

 

 

Here you will see where the inner mount will have to be cut to allow room for the LeSabre cluster to slide in and sit flush with the outer trim bezel. I've traced some lines out where it will need to be cut. You will have to test fit the cluster until you get the right spot where it will be mounted and how deep it will go inside.
















TEST FIT!!!!!!














 

 

 

 

You will need to cut out the bezel so you can see the LeSabre gauges....duh. Cut out the two vertical columns I have marked in this picture. You may have to cut more out later on but for now....just cut where I have marked in this picture.


 

 

 

 

Now it's time to start to wire the cluster up to the Turbo Regal!


WIRING DIAGRAM

Sorry so huge but the older guys will thank me...

Cluster to C1 Connector








 

 

 

 

 

Locating the TACHOMETER WIRE and the SPEED SENSOR





 

 

 

 

 

 

You will need either need to buy a Caspers Electronics Harness Adaptor or you can just cut and splice the original wires to the LeSabre harness connector. That's a more permanent modification but, whatever you like is your business. I try to keep it easily removable if I should sell the car or want to install the cluster in another vehicle.




Three additional wires will have to be added to the factory "C1" connector. YOU DO NOT HAVE TO REMOVE ANY FACTORY WIRES FROM THE ORIGINAL C1 CLUSTER CONNECTOR. Leave them all connected as they come from the factory!

The three wires are the TACHOMETER, SPEED SENSOR and the TEMP GAGE SENDER.

NOTE: When adding additional wires to the car, I try to use the correct color coded wire so it can be easily diagnosed in the future if needed. I got the additional wire from a 1987 Buick Regal...just a regular N/A Regal will do....or any other car for that matter. Just peel the donor harness back and cut the wires to length as needed. You can do this while at the salvage yard too.









 

 

 

 

 

 

During the road test routine after I got the harness made, I found that the alternator would stop charging at an idle when sitting at a stop light for an extended amount of time. To cure this, I soldered in a 470 Ohm resister between the ALTERNATOR brown wire on terminal 3 and IGN PWR terminal 1...located on the Casper's Electronic adapter. You can see the resister in the picture on the lower right soldered in terminals 1 and 3. Also, the idiot light on the LeSabre cluster would stay lit up even though the alternator was charging. The 470ohm cured this too.


 

 

 

 

 

Mounting the temperature sensor/sender.
The new 3 wire temperature sender must be for a analog gage cluster, so I got one from the salvage yard off the car I got the gauge cluster from. The sender is actually two senders in one. One is for the ECM and the other is for the temp gage in the cluster.

The new sender will be mounted where the original ECM temp sensor screws in the intake manifold just above the cam sensor. You will have to cut the original two terminal harness plug off and solder the new 3 terminal plug on your existing harness. You might be able to remove the two original terminals and put them in the three terminal connector...I didn't try that but it might work.

YELLOW to YELLOW
BLACK to BLACK
GREEN to TEMP GAUGE <---MUST BE CONNECTED TO THE GAUGE TERMINAL ON THE CLUSTER...NOT TO THE CLUSTER'S LED LIGHT TERMINAL.



There will be an additional wire that will have to be added to the harness since the original cluster didn't have a gauge. The wire has to be run through the firewall and then up to the original C1 cluster connector. The original single wire Turbo Regal temp sender will still be used for the idiot light on the LeSabre cluster.






 

 

 

 

 

You will have to add an EXTERNAL BRAKE WARNING and a CRUISE light bulb socket if you want to keep those. I'd recommend keeping the BRAKE WARNING light working since it could possibly save your life.
If your car has SECURITY you can also add that as well. Another possibility would be to add a POWER INJECTION light just for the fun of it!

The picture is the finished adaptor harness. It can be easily removed if you every wanted to put your original cluster back in the car...WHY would you ever want to do that?



 

 

 

 

 

 

Modifying a speedometer to accept two speed sensors.
The stock 1992 LeSabre speedometer needs 4000 pulses per mile (ppm) from a speed sensor to read accurately. Unfortunately, the Turbo Regal only uses a 2000 ppm sensor for the ECM and the CRUISE CONTROL. I've searched the internet for a cheap easy solution that could output a 2000 & a 4000 ppm signal but found nothing. So I figured out a way to "cheat" by using a factory 2000 ppm speed buffer.

The factory speedometer has a propeller-like metal "blade" inside the head unit that the speed sensor gets it reading from. It reads it by emitting a infrared light beam from the end of the sensor harness and "bouncing" it back into the harness off of the rotating "blade" on the shaft. This "blade" gives the speed sensor "2 pulses" for every revolution. So, in one mile of travel, the speed sensor will receive 2000 pulses of light to the sensor/buffer to tell the ECM & cruise control how fast the car is traveling. So, I thought that if I doubled the amount of "blades" on the shaft, that would effectively turn a 2000 ppm sensor into a 4000 ppm sensor at a very cheap price and will still be using factory parts!

Not knowing if the original 2000 pulse per mile speed buffer could read twice as fast as it was designed to do, I began this unknown quest by using an old 1983 Malibu speedometer core as the source and keeping my factory speedometer just in case if this didn't work. You will need to get a speedometer from a early 80's GM with Computer Command Control or an ECM...same thing...haha. Other makes and models will probably work also....I just happen to have a Malibu unit that I've been holding onto for a long time.

Disassemble the speedometer as shown in the following pictures. Remove the needle, face, all the gears and the odometer. Remove the flat black disk from the needle shaft and everything else except the shaft that the speedometer cable drives. After it's apart, you will see the "propeller-like thingy" I was talking about earlier. Take the black disk and mount it on the speedometer "thingy" that spins....see picture.

I used Ultra Black RTV since that works very well in other applications.












Sand off all the black paint on the disk until it becomes shiny. Then, place two pieces of tape ( in a crossed pattern) over the disk and paint it FLAT BLACK. DO NOT USE SHINY PAINT. Here you see where the additional speed sensor will get it's reading from. It's now going to read from 4 shiny places on the disk making the speed sensor/buffer receive 4 pulses per revolution instead of the usual two pulse per revolution. Pretty simple huh?!





 

 

 

 

Making a speed sensor mount and mounting the sensor.
I used a piece of thick Plexiglas since it was easy cut and drill. If you are actually thinking about doing this project I'm sure you're competent enough to know how to make a simple bracket. See pictures on the right.

Make sure you get the speed sensor over the four shiny spots on the disk or it will not read properly. I found that the distance from the disk to the sensor can vary and doesn't effect the speedometer reading during testing. Mine is probably about 3/16" away from the disk.


















Here are BOTH speed sensor connectors mounted to the speedometer head. The unit will placed under the dash just above the fuse panel. Make sure you don't get any wires near the rotating parts when securing it.









 

 

 

 

 

The second (4000ppm) speed sensor buffer will wiring into the same B+ and GROUND as the original buffer. The converted 4000ppm sensor's BROWN wire will need to be run up to the Turbo Regal's C1 connector behind the cluster.


 

 

 

 

 

TEST DRIVE with a Navigation System to confirm it will work. As you can see, the speedometer reads correct! Whoo-hoo!
NOTE: My car does not have the correct size tires on the rear...they are slightly taller than factory size tires. The speed of the car is one to two mph higher than the speedometer is reading (at 70mph) when compared to the cars ACTUAL speed on the Navigation





 

 

 

 

 

Mounting the idiot lights.
You might want to do something different and less complicated to get your idiot lights working but here's how I done mine. Remove the guts from the LeSabre's cluster so all you have is the frame.

To get the idiot lights mounted, I got the LeSabre's "information center" that's located on top of the dashboard of the same car that the cluster comes from...92-92 LeSabre. I cut off the ends of the info center to get two housings as seen in the pictures. I then mounted them to the bottom of the LeSabre cluster using JB Weld. That worked very nise and it's mounted solid! Now, there's a place to attach 4 idiot lights.











 

 

 

 

The Bezel lens.

The lense is made from a piece of Plexiglas. Very thin and was bought from your local Lowe's store. The bezel lense will be something that you might want to do different than me. I used the original idiot light boards from the Turbo Regal's cluster and placed them at the bottom of the cluster to make it look even more factory!

NOTE: The Plexiglas comes covered with protective covers on each side of it. DO NOT TAKE IT OFF!! If you take it off you might not be able to cut it very good if you use a power tool (like I did). The fast cutting action of the blade will melt the plastic back together after you get it cut. The protective cover will let you saw it without a problem.



Here is the lense that will fit into the trim bezel. It will also have all the idiot lights shining though it at the bottom.

















Almost finished! Just got to put some silver pin stripping around the bezel to make it appear stock(ish).


 

 

 

 

 

 

 




1987 Grand National Aerocoupe

 

 

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