Gauge Needles -- Replaced, But In Not Reading Correctly

[John Martin]

I recently rebuilt the needles in my instrument cluster by putting SMT LEDs on a thin circuit board and replacing the old plastic LED arrays. They light up perfectly, but they read incorrectly because they start below zero.

Two possibilities:

1) The circuit boards I installed are heavier than the plastic ones the needles came with, or

2) I need to unhook the cluster and reposition the needles to zero BEFORE hooking the cluster back up to power.

Any ideas?

Thanks,

JM

[Lexucan]

I recently rebuilt the needles in my instrument cluster by putting SMT LEDs on a thin circuit board and replacing the old plastic LED arrays. They light up perfectly, but they read incorrectly because they start below zero.

Two possibilities:

1) The circuit boards I installed are heavier than the plastic ones the needles came with, or

2) I need to unhook the cluster and reposition the needles to zero BEFORE hooking the cluster back up to power.

Any ideas?

I refitted my gauge needles with new SMT LEDs as well (one per needle), and two of the needles (speedo and fuel gauge) were reading low after I reinstalled the cluster. The fuel gauge needle was easy to recalibrate. I just gently moved the tip of the needle with my finger until it was at the right reading. I didn't have to remove it from the face of the gauge. The Speedo needle was a little trickier. It was resting below "0" when the car was stationary. What I had to do was to rebalance the needle by adding weight to the base end so that when the needle was reinstalled, the tip rested right in line with the "0" mark. To do this, I melted a very tiny spot of solder onto the little metal tab at the base of the needle (see photo). Then I reinstalled the needle onto the speedo gauge and tested it. I had to do this probably 4 times, adding a tiny bit more solder each time to the metal tab and retesting it, until the added weight was enough to properly balance the needle. The key is to add just a very small bit of solder at a time and retest it. Adding more solder to achieve the right weight balance is easy. Removing solder (if you add too much) can prove to be not quite so easy. :(

If you are able, post some pics of your new needles. I'd be interested to see how they look with the new illumination. How many LEDs did you use for each?

[John Martin]

I took the needles off and reweighted them as you suggest. I used some lead tape that is designed for adjusting the swingweight of golf clubs, basically a lead strip with a sticky back. The key to installation is, I think, to leave the smoked cover off of the cluster, install it, adjust the needles to the correct positions, drive around to make sure everything is aligned, and then install the smoked cover and cluster bezel.

I used four red 60mcd SMT 1206 LEDs on the long needles and three on the short, mounted on strips of copper-clad circuit board cutr from a Radio Shack breadboard. I used a single SMT resistor -- 150 and 270 OHM, I think. Here's a good calculator for the circuit -- http://www.hebeiltd.com.cn/?p=zz.led.resistor.calculator

I'll post pictures tomorrow. The needles are little funky looking. I expected the translucent slits in the needles to disperse the light more evenly.

If I were to do it again, I would try to find an SMT LED with a voltage drop closer to 1V rather than the 1206's 2-2.2V. That would allow a chain of ten or so of them to be used in the long needles. The other option would be to find a smaller SMT package with a lower current that would fit horizontally in the needle, and run the LEDs in parallel instead of serially. Basically, recreate the original lighting. I would also like to see what it would look like to turn the LEDs to face downward so that the needles are backlit.

I now have an additional cluster and plenty of raw materials, so maybe I'll experiment.

JM

[Lexucan]

I took the needles off and reweighted them as you suggest. I used some lead tape that is designed for adjusting the swingweight of golf clubs, basically a lead strip with a sticky back. The key to installation is, I think, to leave the smoked cover off of the cluster, install it, adjust the needles to the correct positions, drive around to make sure everything is aligned, and then install the smoked cover and cluster bezel.

The reason I used solder to counter-weight the needle was that I wanted a method that I wouldn't need to worry might perhaps come loose at some later time. Solder is pretty much permanent.

I initially made the mistake of covering the back of each needle with a small strip of duct tape, thinking it could help to direct the light from the LED along the length of the needle and also prevent any light from reflecting off the face of the gauges. Unfortunately, after a few days the duct tape strips started to peel away from the needles. I suppose the temperature inside the cluster during operation of the car was high enough to start weakening the adhesive. So, I had to take out the cluster again to remove the strips of tape before they fell off!

I was happy to discover that even without the tape, there was no visible LED light reflection behind the needles and the dispersion of light along the length of the needle was no worse without the tape than with it. I chose to use one LED per needle, positioned at the tip. So, only a portion of each needle is illuminated (see photo) but the effect is actually pretty nice (IMHO) and the gauges are very readable in all levels of ambient light.

I used the same installation method as you - putting the cluster back into place in the dash with the smoked window off, then installing the needles and testing them before replacing the cover. The cover is next to impossible to remove with the cluster in the dash, so making sure that everything was working correctly first was important before snapping the smoked cover back into place.

I look forward to seeing your photos.

[John Martin]

Here are a bad picture that shows the multiple LED approach, done with a flash so LEDs are washed out.

BTW, how can I include the photo in the body of the post?

JM

Detail1.bmp

[Lexucan]

Here are a bad picture that shows the multiple LED approach, done with a flash so LEDs are washed out.

BTW, how can I include the photo in the body of the post?

JM

Interesting look to your needles. Without the bright flash from your camera, does the illumination from your LEDs appear to blend together more? With four LEDs in one needle I would have thought it would appear more fully illuminated from end to end without the bright spots, but photos can be deceiving.

I use photobucket.com to host my image files and then link them to my posts using the "insert image" button at the top of the message window.

[John Martin]

Yes, the lighting is as it appears, a line of teardrops. The teens think they look cool.

If I redo this again, I will use the smaller 0603 packaging and run them in parallel down the length of the needles.

Getting the weighting correct is pretty tricky using the SMT 1206s and a curcuit board.

JM

[liquidwrench]

Yes, the lighting is as it appears, a line of teardrops. The teens think they look cool.

If I redo this again, I will use the smaller 0603 packaging and run them in parallel down the length of the needles.

Getting the weighting correct is pretty tricky using the SMT 1206s and a curcuit board.

JM

I had my cluster rebuilt at I believe it was lightech. Cost $100.00 and only took about one week. But the temp gauge is reading about 1/8 higher than before. Can I make an adjustment ?

[dcfish]

I recently rebuilt the needles in my instrument cluster by putting SMT LEDs on a thin circuit board and replacing the old plastic LED arrays. They light up perfectly, but they read incorrectly because they start below zero.

Two possibilities:

1) The circuit boards I installed are heavier than the plastic ones the needles came with, or

2) I need to unhook the cluster and reposition the needles to zero BEFORE hooking the cluster back up to power.

Any ideas?

I refitted my gauge needles with new SMT LEDs as well (one per needle), and two of the needles (speedo and fuel gauge) were reading low after I reinstalled the cluster. The fuel gauge needle was easy to recalibrate. I just gently moved the tip of the needle with my finger until it was at the right reading. I didn't have to remove it from the face of the gauge. The Speedo needle was a little trickier. It was resting below "0" when the car was stationary. What I had to do was to rebalance the needle by adding weight to the base end so that when the needle was reinstalled, the tip rested right in line with the "0" mark. To do this, I melted a very tiny spot of solder onto the little metal tab at the base of the needle (see photo). Then I reinstalled the needle onto the speedo gauge and tested it. I had to do this probably 4 times, adding a tiny bit more solder each time to the metal tab and retesting it, until the added weight was enough to properly balance the needle. The key is to add just a very small bit of solder at a time and retest it. Adding more solder to achieve the right weight balance is easy. Removing solder (if you add too much) can prove to be not quite so easy. :(

If you are able, post some pics of your new needles. I'd be interested to see how they look with the new illumination. How many LEDs did you use for each?

If you pull that cover off there is a brass weight behind it. That is the way the needle should be adjusted.

Yes, the lighting is as it appears, a line of teardrops. The teens think they look cool.

If I redo this again, I will use the smaller 0603 packaging and run them in parallel down the length of the needles.

Getting the weighting correct is pretty tricky using the SMT 1206s and a curcuit board.

JM

I had my cluster rebuilt at I believe it was lightech. Cost $100.00 and only took about one week. But the temp gauge is reading about 1/8 higher than before. Can I make an adjustment ?

Yes, There is 1/4 turn adjustment available, You have to pull the needle off and replace it where it belongs. This can be done while the cluster is still in the dash. Remove the cluster molding and you will see 4 phillips screws that hold the plastic cover, Remove the screws and pull the cover off. You will be able to access the needles then. You can even do it when the car is running if you want. Attached is an old needle fix for what it's worth. It is always an option.

Fix_for_Lexus_Needles.pdf

[liquidwrench]

Yes, the lighting is as it appears, a line of teardrops. The teens think they look cool.

If I redo this again, I will use the smaller 0603 packaging and run them in parallel down the length of the needles.

Getting the weighting correct is pretty tricky using the SMT 1206s and a curcuit board.

JM

I had my cluster rebuilt at I believe it was lightech. Cost $100.00 and only took about one week. But the temp gauge is reading about 1/8 higher than before. Can I make an adjustment ?

You mean I have to turn it 1/4 or 90 degrees, I hink that would be too much

[dcfish]

Yes, the lighting is as it appears, a line of teardrops. The teens think they look cool.

If I redo this again, I will use the smaller 0603 packaging and run them in parallel down the length of the needles.

Getting the weighting correct is pretty tricky using the SMT 1206s and a curcuit board.

JM

I had my cluster rebuilt at I believe it was lightech. Cost $100.00 and only took about one week. But the temp gauge is reading about 1/8 higher than before. Can I make an adjustment ?

You mean I have to turn it 1/4 or 90 degrees, I hink that would be too much

You can place the needle anywhere within the 1/4 turn adjustment, Pull it off and put it back on where you want it. It's that easy.

[logic]

I recently rebuilt the needles in my instrument cluster by putting SMT LEDs on a thin circuit board and replacing the old plastic LED arrays. They light up perfectly, but they read incorrectly because they start below zero.

Two possibilities:

1) The circuit boards I installed are heavier than the plastic ones the needles came with, or

2) I need to unhook the cluster and reposition the needles to zero BEFORE hooking the cluster back up to power.

Any ideas?

Thanks,

JM

Set the needles back at zero than hold it up to see where they fall, move them back and forth until they are at zero when the cluster is standing up. No need to mess with the temp or gas needles.

[SRVCM]

I recently rebuilt the needles in my instrument cluster by putting SMT LEDs on a thin circuit board and replacing the old plastic LED arrays. They light up perfectly, but they read incorrectly because they start below zero.

Two possibilities:

1) The circuit boards I installed are heavier than the plastic ones the needles came with, or

2) I need to unhook the cluster and reposition the needles to zero BEFORE hooking the cluster back up to power.

Any ideas?

Thanks,

JM

Set the needles back at zero than hold it up to see where they fall, move them back and forth until they are at zero when the cluster is standing up. No need to mess with the temp or gas needles.

Ok, I know my post my be a little old in regards to the discussion but I have a question after reading all the "Fixes"

1)Can the needles be adjusted by some means i believe are identified as removing some cover behind the needle and adjusting some screw??

2)The Fuel guage (Which is my reason for posting) can be adjusted how?

A. moving it to the correct position(Which I tried and doesnt work)

B. Removing some conver behind the needle and adjusting manually with some sort of weight behind the cover?

C. Placing solder on the back weight to rebalance?

If someone can provide a more detailed instruction as to how to do the adjustment I would appreciate it very much!!!

I am in the process of adjusting my needles after doing the Luxcan SMT led replacement to my needles and will keep all posted as to how my adjustment goes as well.

srvcm

[Lexucan]

1)Can the needles be adjusted by some means i believe are identified as removing some cover behind the needle and adjusting some screw??

There is no screw behind the needle for making adjustments.

2)The Fuel guage (Which is my reason for posting) can be adjusted how?

First, fill your gas tank to full so you know where the gauge needle should be sitting when it is reset. Then, carefully remove the needle from the gauge and place it back on so that it is indicating a full tank.

[SRVCM]

1)Can the needles be adjusted by some means i believe are identified as removing some cover behind the needle and adjusting some screw??

There is no screw behind the needle for making adjustments.

2)The Fuel guage (Which is my reason for posting) can be adjusted how?

First, fill your gas tank to full so you know where the gauge needle should be sitting when it is reset. Then, carefully remove the needle from the gauge and place it back on so that it is indicating a full tank.

Thanks, I tried that and found my fuel guage was broken and will not allow it to read full. So I purchased a whole new instrument cluster at my local junk yard($30.00) and will install it friday. I check the guage by following the repair guide offered at the beginning of the forum. It states to check for continunity between three screws at the back of the fuel guage and I found between pins B and C there is no continunity :cries: so ill remove the fuel guage from the cluster i purchased and put it in mine. I checked the guage and it reads correctly according the the repair manual.

Luxucan I also did my dash like yours and I LUV it!!

Anyone need a cluster parts??? email me at srvcm@yahoo.com

[raylove1]

1)Can the needles be adjusted by some means i believe are identified as removing some cover behind the needle and adjusting some screw??

There is no screw behind the needle for making adjustments.

2)The Fuel guage (Which is my reason for posting) can be adjusted how?

First, fill your gas tank to full so you know where the gauge needle should be sitting when it is reset. Then, carefully remove the needle from the gauge and place it back on so that it is indicating a full tank.

Thanks, I tried that and found my fuel guage was broken and will not allow it to read full. So I purchased a whole new instrument cluster at my local junk yard($30.00) and will install it friday. I check the guage by following the repair guide offered at the beginning of the forum. It states to check for continunity between three screws at the back of the fuel guage and I found between pins B and C there is no continunity :cries: so ill remove the fuel guage from the cluster i purchased and put it in mine. I checked the guage and it reads correctly according the the repair manual.

Luxucan I also did my dash like yours and I LUV it!!

Anyone need a cluster parts??? email me at srvcm@yahoo.com

how can you remove the needle i try pulling on mine and it dosent seem to come off??

[Lexucan]

how can you remove the needle i try pulling on mine and it dosent seem to come off??

The needles do pull off but sometimes they are difficult to remove. I wouldn't try to use anything but your fingers to pull on them as a tool such as pliers could crack or crush the plastic they are made of. It might take a considerable amount of work to get a stubborn needle loose but it will eventually let go. Don't be too aggressive with it, but grasp the needle around the base where it attaches to the gauge and keep applying gentle pulling force with your fingers. You'll get it off.

Edit: If you are still having problems, what you might try is using two 8-12" pieces of string, fishing line, or fine wire. Slide the first piece under the needle and out the other side right where the needle connects to the gauge (at the base). And using the second piece, do the same by sliding it under the other side of the needle/gauge attachment point the same way. Then you can grab all four loose ends of the string, line, or wire to wrap around your finger, giving you extra upward pulling force right at the base as you, at the same time, grasp the base of the needle with your fingers to pull it loose from the gauge. What you are essentually doing is creating a little sling support under the needle, right at the point at which it connects to the gauge. I hope my explanation makes sense...and that the idea works.