gauge cluster conversion question

one attachment did not make it, here is the breakdown for the cluster plug new configuration

I got the temp and oil presure gauges figured out, I was having a brain fart about being able to read resitance to ground. I was only considering the one wire from the sensor to the gauge and forgot that the sensor is grounded to the block and the gauge has seperate power source. The gauge is just an OHM meter reading the resistance through the wire. Of course you cannot read resistance with only one wire but with the ground in the cluster and the ground that the gauge makes to the block, you have a loop that the resistance can be measured with the gauge/ohm meter. still waiting on the tach and fuel gauge (holidays have slowed down the post man) but I was able to purchase the new sending units. the oil presure sending unit for the guage was $18 and the water temp gauge was $16. I wired the sending units to the gauge cluster with jumpers from my battery to the power and ground inputs on the cluster and I was able to make everything work. Using a heat gun, I was able to make the water temp sending unit operat the gauge. I could not do this with the fuel gauge but just grounding the sending unit wire would make the gauge move back and forth. I am going to try to put a T at the water temp sending unit so that I can use both sending units. Just in case I am not looking at the gauge, I will have a light to notify me of an over temp issue. I am also going to wire the low coolant to the same check engine light. I would try to T the oil presure units and use both also but I dont think there is enough room at the location of the oil presure sending unit. Still looking into doing this. I would like to have the check engine light come on with either low oil presure, low coolant, or high coolant temp since the gauges dont always catch your eye when they are in the red. Did not remember to get the part numbers for the sending units but I will post them in the next update. I also tested all of the lights in the cluster and everything works. Just have the tach and fuel gauge to get installed and wired and the cluster will be done.

Keep up the good work!

thanks, M1031CMT for the encouragement.

Today I got the new sending units installed. The Oil presure sending unit is Master Pro 2-8136 s996 and the water temp unit is BWD wt359. I went to Lowes and got the brass fittings. The Oil sending units are 1/4 inch fittings and the Water fittings are 3/8 fittings. The are standard brass gas line fittings at Lowes or Home Depot.
Installing both sensors will allow me to combine the output of the Water temp (light), the Low Oil presure (light) and the Low coolant sensor to allow any of the three to light the check engine light that will be located in the speedometer. All three of these sensors are a ground to light. The low coolant sensor is not a ground to light but it goes through a relay so that it acts like a ground to light sensor. I will run new wires to the gage sensors to opperate the gauges. I did not get the wiring done today because I had to take apart the steering column to replace a bad wiper switch. The intermitant wiper switch that has the headlight bright switch is discontinued at the gm dealer and is a special order at the autoparts stores. Still need to check LMC and other classic parts vendors.

I have been quite interested in doing away with the circut board completely. The poor connections of the light sockets seem to be a problem as well as the limited ability to rearrange guages for mods that each of us may make. I have been working 2 jobs so my time is limited however I have thought of totally eliminating the circut board with the use of a cannon plug. It would take a bit of time to do the inital wire up,but I do think that it would elimate the amount of connections that are open to the air. The origional circuts would still be intact and allow us to modify the dash lay out as we progress in out upgrades. What do you guys think?

I am not to worried about the circuit board, I use it on all of the gauges I can. As far as I can tell these have lasted 20+ years. for the cost of the wire and plug you could put a new board on from LMC. If you put a new board in and used some good di-electric grease, they will probably last longer with less problems. The Cluster I got from the 87 burb looks brand new from the back, all of the copper is still shinning. It was easy to build the gen two plug and this could be done with all of them if you wanted.
I got the tach from LMC today but they shipped me the wrong fuel gauge. The tach cannot use the old fuel gauge terminals so it will require its own harness. My tach will be wired to the Dakota Digital module which is mounted above my glove box so none of the wiring for the tach will leave the dash area. I already have the 24volt meter on its own harness and the fuel gauge will have to have its own harness since the cluster has nothing in this area (lower left corner gauge position). I was going to use a new plug but I think I will not spend the money and use the factory plug for all that I can and the other devices will have their own plugs in order to disconnect the harness. The Water temp gauge and oil presure gauge will use the circuit board along with all of the lighs with exception of gen 2.
Here is a pic of the tach, it is a perfect match with the hole for the lights in the bottom. It is going to be a week or so before it is installed and can be tested, I am now waiting on a windshield wiper switch for the steering column and my column is torn appart with ignition switch out and batteries disconnected so until the switch gets here all I can do is wire the tach to the cluster and look at it.

did some work on the cluster today, just trying to prevent the shifter tab from breaking in the future. The wire had already cut almost half way through the plastic tab. I cut a flared copper lug to put around the tab and then JB welded it in place and built up the rest of the plastic also. The flare on the fitting provides a shoulder to help keep the wire in place. I also build my switch panel. I used micro switches I got at Fry's electronics. I soilderd on pigtails. the large black switch is for my front locker. the next three are: torque converter lock up, trans economy mode, and trans manual mode. The two red push buttons are upshift and downshift when in manual mode. The remaining switches are reserverd for lighting. I made an aluminum plat the same size as the plastic stock stereo cover. I managed to get all of the switches in the hole where I did not have to cut the bezel any. The switches are rated for 5 amps at 28v so they should be ok for 10 at 12 volts. I dont plan to run any more than 5 amps through them. Any thing larger will have relays. Still waiting on the fuel gauge, steering column wiper switch and trans controler. The Trans Controler will mount where the 24 volt meter was located.

Good work. Looks like it came originally from GM like that.

Yeah that stupid shift tab has broken on 3 of the 5 CUCV's here. I fixed it the M1009 just last week.



Not the best looking, but it works and the bezel covers it up. And more importantly it shouldn't break again

Looking forward to seeing your dash put back together into the truck!

richingalveston said:

did some work on the cluster today, just trying to prevent the shifter tab from breaking in the future. The wire had already cut almost half way through the plastic tab. I cut a flared copper lug to put around the tab and then JB welded it in place and built up the rest of the plastic also. The flare on the fitting provides a shoulder to help keep the wire in place. I also build my switch panel. I used micro switches I got at Fry's electronics. I soilderd on pigtails. the large black switch is for my front locker. the next three are: torque converter lock up, trans economy mode, and trans manual mode. The two red push buttons are upshift and downshift when in manual mode. The remaining switches are reserverd for lighting. I made an aluminum plat the same size as the plastic stock stereo cover. I managed to get all of the switches in the hole where I did not have to cut the bezel any. The switches are rated for 5 amps at 28v so they should be ok for 10 at 12 volts. I dont plan to run any more than 5 amps through them. Any thing larger will have relays. Still waiting on the fuel gauge, steering column wiper switch and trans controler. The Trans Controler will mount where the 24 volt meter was located.

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Cool mod... it has me inspired to redo mine.... will locate the factory tach, and Fuel gauge from LMC.. Drop my newly installed autometer tach and rewire cluster as you did....

richingalveston said:

I am not to worried about the circuit board, I use it on all of the gauges I can. As far as I can tell these have lasted 20+ years. for the cost of the wire and plug you could put a new board on from LMC. If you put a new board in and used some good di-electric grease, they will probably last longer with less problems. The Cluster I got from the 87 burb looks brand new from the back, all of the copper is still shinning. It was easy to build the gen two plug and this could be done with all of them if you wanted.
I got the tach from LMC today but they shipped me the wrong fuel gauge. The tach cannot use the old fuel gauge terminals so it will require its own harness. My tach will be wired to the Dakota Digital module which is mounted above my glove box so none of the wiring for the tach will leave the dash area. I already have the 24volt meter on its own harness and the fuel gauge will have to have its own harness since the cluster has nothing in this area (lower left corner gauge position). I was going to use a new plug but I think I will not spend the money and use the factory plug for all that I can and the other devices will have their own plugs in order to disconnect the harness. The Water temp gauge and oil presure gauge will use the circuit board along with all of the lighs with exception of gen 2.
Here is a pic of the tach, it is a perfect match with the hole for the lights in the bottom. It is going to be a week or so before it is installed and can be tested, I am now waiting on a windshield wiper switch for the steering column and my column is torn appart with ignition switch out and batteries disconnected so until the switch gets here all I can do is wire the tach to the cluster and look at it.

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can you provide a part number? i looked on LMC truck and was unable to locate this particular tach....

1ton cucv k5 turbo said:

can you provide a part number? i looked on LMC truck and was unable to locate this particular tach....

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They are a little hard to find for some reason. Here is the link:

http://www.lmctruck.com/newparts/cc/ccrpt.htm

The LMC tachs only show up on line not in catalogs yet.
Attached is a picture of mine with the wiring, you need to bend the tabs over or cut the back of the housing out. If you cut the back of the housing you will also have to cut the circuit board and that is something I did not want to do.
After seeing the dimmable red leds, I decided that is what I want. Checking the websight, the lumens are very low compared to white so I decided the interior reflective surfaces must be improved to use these lights. My cluster had a lot of brown/burnt areas around the bulbs wich was not going to help. I used metal tape on the back of all of the gauges and I used crome paint for the interior and the back of the black cover plate. The reflective tape is somewhat brighter than the chrome paint but it was much easier to install the chome paint I also did not want to risk shorting any of the contacts with the tape. While the circuit board was off, I cleaned everything with electrical cleaner and in the areas that I will not use, I sprayed them with liquid electrical tape to protect the unused circuits. attached is a pic of the standard CUCV cluster housing. If you plan to use this as your base for upgraded gauges, you will have to cut alot out and there will be no mounting screw locations for the gauges. I recomend finding a civi cluster to start with. You can buy the cluster, circuit board and all of the gauges from LMC but from my quick addition you will pay more than $700 for all the parts.

Thanks... Ive already modded my cluster, a bit.... ( relocated the GEN lights to panel with GEN meter, added air press gauge.. and gutted my top to left ports for Auto meter gauges...) i wish i could have found this tach a year ago... Wouldve saved me ALOT of money... oh well...lol I will keep most of my autometer gauges, but just swap tach for a fuel gauge when i add my Boost and pyro into the old GEN locations.. doing this to try and give it more of a clean look, as the current fuel gauge just takes up too much space... IMHO... and having a larger tach will be more useful for me...

I got the fuel gauge and installed it today, since it goes where the clock is the post are not there and so I had to cut the back out for it to fit and to run the wires. It does mount into the lower left corner of the civy cluster. I also cut the cluster plug from the cucv today and labled all of the wires upon removal. The plug on the cucv was not the same as the civy plug with regaurds to the way the pins were fixed in the plug, the civy plug you can stick a small pin into the top of the plug and release each pin wich allows you to move pins around to different locations on the plug. The cucv plug would not release the pins, they click into the sides and there is no way to release them so I had to cut the plug off. I was hoping to move the pins to the appropriate location and re-use the plug but this was not possible. I will use the civy plug and splice the wires where needed. I do need to update my spreadsheet on the cucv plug, some are labled as + inputs and they are actually - inputs. I will get the corrections posted in the next update. I hope to get my Red LED lights and finish the cluster install tomorrow. Wont be able to do a full test unitl my wiper switch gets here and I can put the steering column back togather. If I do not recieve it tomorrow, it should be here for sure on monday.

here is the updated cluster plug info.

Got the led's today (thanks to the ss member who posted the led's, can't find the thread to name the person) I installed them in the cluster and tested them with the battery. I can not install the cluster until I get my wiper switch and install it (the column is still torn apart) hopefully this should be here on monday. After the first test, I was not getting enough light to the gauges on the left so I had to cut some of the extra metal from the gauges. I may try to install an additional bulb in the gauges because they are still slightly darker than the tach and speedo. When I get the cluster installed and can use the dimmer, I want it to dim eavenly.
The attached pics are cluster all lit up. I used white single led bulbs in the blinkers high beam and gauge lights which constist of 4x4 light and service engine light in speedo and gen1 and gen2 in tach. not going to have a seatbelt light and the low coolant,high coolant temp and low oil presure lights are all combined into the service engine light
The lit up cluster is before the gauge modification. two pics of before and after the gage mod to allow more light. the last pics are the cluster with just the red lights on after the gage mod.
I also included one pic of the led's and the socket I bought from the same place. these sockets fit perfect and are only $1.49 each. The red Led's are $2.99 and the white is $1.39 each. The sockets are great for circuit board repairs or for those who wish to get rid of the circuit board, I would purchase these. the one I made was easy to make and I used a bigger wire size but since the led's use a fraction of the power of a regular bulb the smaller wire size is not an issue. I am going to use the one I made for my gen 2 light since it has a regular bulb and not led.
The Superbrightleds.com has all of the bulbs for the truck exept headlight. looking to replace all marker lights with leds now that I have a good source. should really help to save the wiring with the much smaller loads.

todays udpdate:
I picked up some shrink wrap number labels in order to document the connections for future trouble shooting and easy removal and reinstallation of the cluster.
I am sure there are other ways to do this but this worked best for me. I wanted to get one big plug to run everything through but I could not find a reasonably priced plug for the 20+ wires. I had the nylon connectors so a connector for each wire was how I decided to do this. At least with these connectors, there is now enough length on the wires to remove the cluster and unplug the wires without having to do all of this under the dash and you can still unplug the plug from the cluster. Attached are the pics of the wiring in the dash with the number labels and connectors. Also one pic of the wires on the back of the cluster. And two spreadsheets. One spreadsheet is the wires from the dash and the other is the wires on the cluster. Wires of the same number connect to each other. I hope to have my wiper switch tomorrow and once it is installed I will be able to install the cluster and test it in the dash.

I was able to get the steering column back togather and the cluster installed and everyting is working with the exception of the water temp gauge. I think the gauge is bad. I can tell that the sending unit is working with my meter but the gauge does not move. I did however find out that the LED lights do not dim with the dimmer however, the red led's are very easy on the eyes and I think not having a dimmer will not be an issue since they are about as bright as I like them to be anyway. I also found my gen 1 needs a rebuild. I get no voltage when at idle and when i rev the motor the output from the alternator jumps from 0 to 15 volts. Looks like I have to order rebuild kits for the alts. and a new temp gauge to finish the project. Since the cluster is just sitting on the steering column and not installed, I did not take any pics. Tach is working just needs to be fine tuned. It shows 800 rpm at idle and I think that is a little high. going to have to go to my mechanic to get an alternate timing source to fine tune the Dakota digital module.

M1031CMT said:

Good work. Looks like it came originally from GM like that.

Yeah that stupid shift tab has broken on 3 of the 5 CUCV's here. I fixed it the M1009 just last week.

View attachment 401802

Not the best looking, but it works and the bezel covers it up. And more importantly it shouldn't break again

Looking forward to seeing your dash put back together into the truck!

Click to expand...

This broke in my G30 at about 275k miles as well. A lot of the parts are interchangeable with the CUCV.

So I was able to verify my wiring this week, all my gauges work. It looks like richingalveston has already posted his wiring pin-out, and I think we have the same thing, but maybe this will help someone.