U.S. CitiesCity-Data Forum Index
Go Back   City-Data Forum > General Forums > Science and Technology
 [Register]
Please register to participate in our discussions with 2 million other members - it's free and quick! Some forums can only be seen by registered members. After you create your account, you'll be able to customize options and access all our 15,000 new posts/day with fewer ads.
View detailed profile (Advanced) or search
site with Google Custom Search

Search Forums  (Advanced)
 
Old 02-13-2017, 05:02 PM
 
Location: SC
4,940 posts, read 2,906,796 times
Reputation: 6943

Advertisements

Hello all, I am looking for... a place to start and some advice:
  • I have a 22 year old car.
  • The instrument cluster is only working intermittently.
  • There are times when the entire cluster works - and it works with no visible faults.
  • When it is not working, there can be several fail modes, including:
    • The Tachometer, Speedometer, Odometer do not work at all.
    • The Tachometer and speedometer work, but the odometer does not light at all.
    • The Tachometer and speedometer work, the background light is on at the odometer, but no digits are displayed.
  • There is a suggested fix - removing and replacing bad capacitors. Some say this works for them, so say it does not.

Before I take my cluster apart, it seems I should be able to bench test the unit. I would think that I should be able to remove the cluster to my workbench, attach a power supply and reading the schematics figure out exactly what is and is not working. Q1: Am I correct?

Q2: If the above is correct, I assume, that I should be able to remove the cluster and attach the connector harness to some kind of data acquisition device, start up the car, drive around, download the recorder to my computer, and see (using the bundled software) if I am getting constant voltage to the connectors under the correct conditions?

Q3: Further, if all of the above is also true, then can anyone tell me what kind of device I would need to test for voltage/signals to the connectors?

There are 4 connectors at the back of the cluster:
  • One 12 pin connector seems to go to the speedometer/odometer
  • One 12 pin connector to the tachometer
  • One 10 pin connector and one 8 pin connector appear to connect to the Oil Pressure, Fuel level and Temperature Gauges (which all work all the time).
If my suppositions are correct about connecting a data logger, then I am guessing I need an instrument that can handle 12 channels at a time (if I were to test the tach circuit separately from the Odo and Speedo) or 24 channels if I wanted to test them all at the same time.

Looking around the net, I find this instrument...
https://www.dataq.com/products/di-145/
It looks like the kind of device I need, except for the fact it only supports 4 channels.

Q4: Would it be correct to buy 3 of these units and plug them all in at the same time to one of the connectors? Buying 6 for the two connectors seems overkill if I cannot find a 24 channel unit. Q5:Is there anything more I can learn by recording both connectors instead of one at a time?

Again, I am not versed in any of this, but I am willing to dive in and try - even if I destroy the cluster while learning (I have a backup cluster I took from a dead car).

Any help or suggestions would be appreciated.
Reply With Quote Quick reply to this message

 
Old 02-13-2017, 08:46 PM
 
Location: Somewhere in northern Alabama
14,750 posts, read 43,547,533 times
Reputation: 20982
Those are classic signs of an intermittent open circuit due to corrosion over time.

Rather than spend a bucket o' money, buy two 12 pin connector sets and clip and replace the existing ones. If it works, you owe me a coffee. If it doesn't, then you get to play more.
Reply With Quote Quick reply to this message
 
Old 02-13-2017, 11:00 PM
 
32,234 posts, read 31,461,203 times
Reputation: 12601
If you have not done any other troubleshooting before tearing everything apart try reseating the connectors, jiggle some wires, spray with electronics cleaner or try what Harry suggested. etc.

Bad capacitors can usually be identified by inspecting them, bulging tops etc.
Reply With Quote Quick reply to this message
 
Old 02-13-2017, 11:10 PM
 
1,646 posts, read 408,479 times
Reputation: 1557
Seen bad capacitors physically burnt and smell burnt too.

If it work sometimes though, it's probably not the capacitors. Probably bad stepper motors or connections like others said.

Since the problem is intermittent, it could bench test okay. Intermittent problems are the hardest to diagnose. A lot of times it's a faulty wire or connector.

As for logging data, that's going to be tough if it's not OBD2.

Edit:just read that this is a digital speedometer in that case it has no stepper motors. This will be tough. Do you have a schmatic for the cluster?
Reply With Quote Quick reply to this message
 
Old 02-14-2017, 10:52 AM
 
Location: SC
4,940 posts, read 2,906,796 times
Reputation: 6943
Quote:
Originally Posted by thecoalman View Post
If you have not done any other troubleshooting before tearing everything apart try reseating the connectors, jiggle some wires, spray with electronics cleaner or try what Harry suggested. etc.

Bad capacitors can usually be identified by inspecting them, bulging tops etc.
Unfortunately, the capacitors are internal to the cluster. It will have to be disassembled to see if they are bad.
Reply With Quote Quick reply to this message
 
Old 02-14-2017, 10:56 AM
 
Location: SC
4,940 posts, read 2,906,796 times
Reputation: 6943
Quote:
Originally Posted by ShiverMeTimber View Post
Seen bad capacitors physically burnt and smell burnt too.

If it work sometimes though, it's probably not the capacitors. Probably bad stepper motors or connections like others said.

Since the problem is intermittent, it could bench test okay. Intermittent problems are the hardest to diagnose. A lot of times it's a faulty wire or connector.

As for logging data, that's going to be tough if it's not OBD2.

Edit:just read that this is a digital speedometer in that case it has no stepper motors. This will be tough. Do you have a schmatic for the cluster?
Yes. I will have to learn to read it of course!
Reply With Quote Quick reply to this message
 
Old 02-14-2017, 11:03 AM
 
Location: Mount Laurel
4,028 posts, read 6,464,361 times
Reputation: 3169
Before you get any instruments. Get a hold of the electrical repair manual for your specific car.
Reply With Quote Quick reply to this message
Please register to post and access all features of our very popular forum. It is free and quick. Over $68,000 in prizes has already been given out to active posters on our forum. Additional giveaways are planned.

Detailed information about all U.S. cities, counties, and zip codes on our site: City-data.com.


Reply
Please update this thread with any new information or opinions. This open thread is still read by thousands of people, so we encourage all additional points of view.

Quick Reply
Message:


Over $99,000 in prizes was already given out to active posters on our forum and additional giveaways are planned!

Go Back   City-Data Forum > General Forums > Science and Technology
Similar Threads

All times are GMT -6.

2005-2017, Advameg, Inc.

City-Data.com - Archive 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32 - Top