Who on here is REALLY good at electrical?

mirage83 · 04-18-2011, 12:00 AM

I've got some serious issues with the cluster in my '88 and could use some help.

The cluster housing has been checked and all continuity checks were good, all the gauges themselves seem to be okay, but the #1 speed sensor, the fuel gauge, and the oil pressure gauge are all non-functional.

Any thoughts or advice will be appreciated.

cre · 04-19-2011, 05:04 AM

Quote:

Originally Posted by mirage83

I've got some serious issues with the cluster in my '88 and could use some help.

The cluster housing has been checked and all continuity checks were good, all the gauges themselves seem to be okay, but the #1 speed sensor, the fuel gauge, and the oil pressure gauge are all non-functional.

Any thoughts or advice will be appreciated.

http://www.cygnusx1.net/Supra/Librar...x?S=Main&P=136

The speedometer has nothing to do with the rest. If your other gauges such as the tach, boost or battery gauge, etc are functioning then the issue is most likely a burnt trace in the flexible circuit on the back of the cluster.

mirage83 · 04-19-2011, 11:34 PM

Would a burned trace show up in the continuity tests on the various locations on the back of the cluster as shown in the TSRM for gauge problem testing?

cre · 04-20-2011, 06:35 AM

On those type of circuits a burnt trace is generally VERY obvious and hard to miss with just a visual inspection; Fractures are harder but as this isn't subject to much flexing it's a moot point.

I don't recall the test procedure, however I'm sure it's not very in depth. I suggest you use the TEWD and follow each end back to it's source trace where the harness connects. Check if the couple circuits you're having trouble with share a common trace.

mirage83 · 04-20-2011, 07:23 PM

Well, I decided to do a quick swap to check whether the cluster housing and such was bad, but the replacement unit I put in displayed the same issues as my original, so I'm (for the moment at least) ruling out the cluster as the culprit.

Gotta get this thing running right, meaning I'm reduced to going through the motions you noted and have started tracing each circuit from it's particular cluster plug backwards. Tedious, but I can't see any other realistic options to finding these problems.

Next time I decide to rescue a car in this condition, somebody please get proactive and put me out of my misery to come.

cre · 04-20-2011, 08:26 PM

Don't test for a break, start with the 7.5A Gauge fuse and trace for voltage drop across the circuit.

mirage83 · 04-21-2011, 04:55 PM

Okay, I'll take that route and see what turns up. I appreciate the assist.

04-20-2011, 06:35 AM	#4
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	On those type of circuits a burnt trace is generally VERY obvious and hard to miss with just a visual inspection; Fractures are harder but as this isn't subject to much flexing it's a moot point. I don't recall the test procedure, however I'm sure it's not very in depth. I suggest you use the TEWD and follow each end back to it's source trace where the harness connects. Check if the couple circuits you're having trouble with share a common trace. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

04-20-2011, 08:26 PM	#6
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Don't test for a break, start with the 7.5A Gauge fuse and trace for voltage drop across the circuit. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

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04-18-2011, 12:00 AM	#1
mirage83 12psi boost Join Date: Feb 2007 Location: Georgia Posts: 359	Who on here is REALLY good at electrical? I've got some serious issues with the cluster in my '88 and could use some help. The cluster housing has been checked and all continuity checks were good, all the gauges themselves seem to be okay, but the #1 speed sensor, the fuel gauge, and the oil pressure gauge are all non-functional. Any thoughts or advice will be appreciated.

04-19-2011, 11:34 PM	#3
mirage83 12psi boost Join Date: Feb 2007 Location: Georgia Posts: 359	Would a burned trace show up in the continuity tests on the various locations on the back of the cluster as shown in the TSRM for gauge problem testing?

04-20-2011, 07:23 PM	#5
mirage83 12psi boost Join Date: Feb 2007 Location: Georgia Posts: 359	Well, I decided to do a quick swap to check whether the cluster housing and such was bad, but the replacement unit I put in displayed the same issues as my original, so I'm (for the moment at least) ruling out the cluster as the culprit. Gotta get this thing running right, meaning I'm reduced to going through the motions you noted and have started tracing each circuit from it's particular cluster plug backwards. Tedious, but I can't see any other realistic options to finding these problems. Next time I decide to rescue a car in this condition, somebody please get proactive and put me out of my misery to come.

04-21-2011, 04:55 PM	#7
mirage83 12psi boost Join Date: Feb 2007 Location: Georgia Posts: 359	Okay, I'll take that route and see what turns up. I appreciate the assist.