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17K views 8 replies 2 participants last post by  briano1234 
#1 ·
Hello, all..

Haven't posted in a while, mostly because things have been going pretty good reviving my '82 Rabbit convertible back from the dead. It currently has a recently rebuilt '84 1.8L JH engine in it with about 500 miles on it so far.

The car has always had bizarre gauge issues. The three center console gauges in front of th stick work well, although the oil pressure gauge slowly drops down to pretty much zero after about 15 minutes. It reads accurately (I think) when the engine is started. Right now, that's not a big deal.

Here's the current issue.. the binnacle gauges are, and always have been, acting up like crazy. Here's the symptoms, followed by what I've already done to try and correct the problems.

Symptoms:

1. When key is turned to the "on" position (just pre-crank), none of the dash idiot lights illuminate. The "fasten seat belt" light on the left of the dash does come on.

2. When the car is started, after I "blip" the rpms up once, the tach comes alive and the console gauges read higher. The turn signal indicator light works properly. The high beam indicator light does not work. The gas and temperature gauges in the dash don't work at all. More on that later.

3. Once I've driven for a few minutes, the tach starts behaving erratically, swinging all over the place, and sometimes indicating zero. When it gets stuck on zero, the turn signal indicator light does not work, either. I don't know for sure if the outside turn signals are working at that time. The problem can usually be remedied by racing the engine enough to get the tach moving again... until it starts swinging all over the place and quitting again.

4. When the tach drops and indicates rpms less than what the engine is actually doing, the oil warning light flashes. No buzzer.

That's about it for the symptoms.. no idiot lights on pre-crank, no gas and temp gauges, screwy tach which triggers oil pressure warning light, and no turn signal indicator (and maybe no turn signals at all) when the tach quits completely.

Here's what I've done and or replaced on the car to try and remedy all this before bothering you folks..

1. New fuse block.
2. All new grounds in the engine compartment - battery to frame, frame to transmission, cylinder head to ignition coil bracket. This DID gain me almost an entire volt of charge, much brighter headlights, and much faster windshield wipers.
3. I just ripped out the dash cluster and followed Brian's recommendations found in the DIY section of the cabby-info site. The gas and temp gauges both work properly when fed 9 volts through their associated posts on the back of the cluster. I cleaned all the contact nuts, washers, and traces on the mylar, added the electrical tape to increase the contact at the large ribbon connector per Brian's advice, and I also spliced in an additional cluster ground from the brown wire second from the end of the ribbon connector to the frame in the dash.
4. I was going to swap in a new voltage regulator, but the spare I had didn't physically fit the space and it was an 8.5V regulator. I believe the correct one should be 10V, yes?

In any case, no joy yet. Could a bad regulator cause all of these problems? I've owned the car about five years, but have only been able to drive it this past summer finally. Now that it's running pretty good, I'd like to start getting serious about making it "right."

Any and all ideas or advice is, as always, GREATLY appreciated. Thank you all for your help in getting me this far over the past year or so.

Best wishes,

Barry
 
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#2 ·
Your issue is one of three things.

1. Your voltage stabilizer needs to be replaced. IT is a KA7810ATE avail at mouser.com for less than a buck, but buy 5 as the 7 dollar shipping is steep for only one.
http://www.mouser.com/ProductDetail...GAEpiMZZMtUqDgmOWBjgL4pthfkKVd4LQ%2bXY9c8I8A=


2. Verify that your ground is good by adding an additional ground to the cluster large white connector pin2.
see: http://www.toplessrabbit.com/forums/viewtopic.php?f=7&t=2542

3. Verify that on pin 14 of the large white connector that you have 12V positive dc.
If you have 12V on that pin, then check the 3rd pin of your voltage stabilizer for 12V.
see: http://forums.vwvortex.com/showthread.php?5378917-help-me-Mr.-Wizard.&highlight=wizard
 
#3 ·
Brian,

Thanks for the quick, helpful reply. Responses inserted below...

Your issue is one of three things.

1. Your voltage stabilizer needs to be replaced. IT is a KA7810ATE avail at mouser.com for less than a buck, but buy 5 as the 7 dollar shipping is steep for only one.
http://www.mouser.com/ProductDetail...GAEpiMZZMtUqDgmOWBjgL4pthfkKVd4LQ%2bXY9c8I8A=

I realize I should have had one of these on hand before even beginning to pull the cluster, but I got impatient. I'll try to source on locally (Radio Shack, perhaps?), but if that doesn't work, to Mouser's site I shall go....


2. Verify that your ground is good by adding an additional ground to the cluster large white connector pin2.
see: http://www.toplessrabbit.com/forums/viewtopic.php?f=7&t=2542

As I said in my original lengthy rambling post, I've already done that. It didn't help, but I'm sure it didn't hurt either.

3. Verify that on pin 14 of the large white connector that you have 12V positive dc.
If you have 12V on that pin, then check the 3rd pin of your voltage stabilizer for 12V.
see: http://forums.vwvortex.com/showthread.php?5378917-help-me-Mr.-Wizard.&highlight=wizard
I read the thread you linked to, and it seems like it will be VERY helpful. Thank you. I'm going to pick up a voltage regulator and then get busy going through those steps. Pardon the stupid question... should the measurements/tests should be done with the binnacle connected, key on, and backprobed through the long connector, or with the binnacle removed and just testing the long connector itself?

Thanks again, Brian.. you're a lifesaver.

Barry
 
#4 ·
Binnacle? If you mean instrument Cluster then yes, you will need the key on, be warry of the 4-way hazard switches 2 separate wires, be sure that you insulate them.
 
#5 · (Edited)
Sorry.. old habit from working on an old Range Rover.. they call the instrument cluster the "binnacle"... that's what I meant. I'm not sure what you mean about being wary of the "4-way hazard switches 2 separate wires." I only have one switch.. did you mean "switch's" rather than "switches?" I'm not trying to be obnoxious or the grammar police.. just trying to figure out what you meant. My emergency flasher switch has one big ol' multi wire connector and one single-wire spade connector (I'm guessing to power the bulb which doesn't work right now, although the flashers do). Are those the two wires to which you're referring?

Hey, while I was in the dash yesterday, I discovered a single wire what wasn't connected to anything, but was terminated with a very thin female spade lug connector.. about 1/2 the width of a standard connector. It was a light brown colored wire near the bottom right of the instrument cluster opening.. near the previously mentioned single wire connecting to the hazard switch. Any ideas what that wire is for? Is it possible it is the second wire you mentioned and that it's supposed to also be connected to the hazard switch? There's a small lug on the back of my switch that looks like it may be the right size to accommodate the wire, but there's a resistor soldered to it and to lug 58b. There's not enough lug left to put the wire on. Is the resistor an original part of the switch, or a PO's work?

Thanks again, Brian. The RadioShack site only lists 5v and 12v regulators, and one variable regulator (which might very well work if set properly), so I guess I'll end up ordering from Mouser.... much as I hate paying $7 shipping for a 65 cent part that costs 65 cents to ship in reality.

Best to you,

Barry
 
#6 ·
Quick update... never mind my question about the two wires. The one that wasn't connected (the light brown one with the small female spade connector) goes to the small lug buried inside the lamp holder on the flasher switch, right? I connected it there, and now my flasher indicator light in the switch works. Yay! A small triumph, to be sure, compared to the instrument cluster hassles still to be solved, but at least it's an improvement rather than a setback.

Barry
 
#7 ·
OK... another update! After doing a little more searching around for some more info about my erratic/quitting tach issue, lots of folks (including Brian and TomC) pointed to the wire coming from the coil as a possible issue in other posts. My coil is new, but the high voltage wires are about 5 years old and the low voltage harness is original. I pulled off and reconnected the low voltage wires at the coil a few times as a quick 'n' easy "cleaning" technique, then on a whim pulled the high voltage wire from the coil. The wire came off in my hand, leaving the termination of the wire inside the coil! I pulled out the termination w/ pliers, reconnected it w/ a good crimp to the end of the wire, and hooked it back up. The car fired right up, ran GREAT.. smoother than ever, and... <drum roll>... perfectly functioning, stable tach! I don't know if the fix was recrimping the high voltage wire or reseating the low voltage wires at the coil, but one of those two things did the trick.

Another side effect was that the dash idiot lights came on correctly, too, prior to starting the car. Haven't had that happen in a while. After driving about 10 miles, I shut off the car. When I restarted it, the dash idiot lights didn't work again... hmmmm. Where exactly does wire 14 on the 14-connector get its positive power?

Still no gas/temp gauges. Gotta be the voltage regulator. I'll get one and report back.

Thanks again..

Barry
 
#8 · (Edited)
Ok, a few days have passed, and I'm getting REALLY good at pulling the instrument cluster out of the car fast.. I'm getting LOTS of practice... sigh...

Here's an update, and a plea for some more ideas...

Got a new voltage regulator and installed it, although it's a 9volt regulator rather than a 10. I figured it'd be worth a shot anyway.. couldn't find a 10V locally. Once installed, I reinstalled the dash, and I HAD fuel and temp gauges.. yay! When they turned on (prior to cranking), the temp gauge and gas gauge went full scale w/ the temp red warning light blinking. Is that normal.. sort of a "gauge test" prior to engine run? AFter I started the car, the temp gauge slowly went back to cold indication and the gas gauge read fairly accurately. I let the car warm up to see if the temp gauge would read accurately. Instead, after a few minutes, both gauges died again. I've had the cluster out about 6 times since then, fussing around cleaning up the contacts on the 14 pad connector, putting another narrow strip of electrical tape underneath the worn contact spots of the pads to raise them a little bit. I've also removed wires 3 and 4 from the 14 pin connector (these are the two that feed the fuel and temp gauges) and gently opened the spring end of the connectors a bit to increase the contact tension on the pad. I did this to the wire that controls the hi-beam indicator too, which has never worked. It now works reliably, as does the tach finally. However, aside from a VERY occasional second or two of life, I still can't get the temp and gas gauges to work. I haven't put a tester on the traces of the flex circuit board yet, but I guess that's next. I did visually inspect it pretty carefully and didn't see any signs of a break. Remember, I have added the electrical tape behind the 14 contact pad, and I have spliced in an additional ground on pin 2. This is driving me nuts.

Questions...

1. The Bentley manual shows the pins on the voltage regulator backwards from what I believe is the standard VR configuration. Brian, you mentioned something similar in one of the threads you linked for me. I thought that the pins were as follows, referring to the pins with the pins facing downward and the metal back of the VR facing away from you.. Left pin is input, center pin is ground, and right pin is stabilized output. The Bentley reverses the input and output pins, with the stabilized voltage present on the left pin. Which is correct?

2. Could a 9V regulator cause all the weirdness I'm still experiencing? Like I said, the gauges seem to move fine, but I just can't get them to stay on. No amount of wire or contact wiggling seems to make a difference.

3. Is the full-scale temp indication prior to engine start a standard thing for the temp gauge?

4. If (shudder) a new circuit board is needed (as the Bentley manual suggests as a solution to MANY problems with the gauges and indicator lights, most of which I've experienced), are they available? I can't find them online. I have an '82 Rabbit convertible.

As always, ANY bit of help or advice is much appreciated. In return, I'd be happy to pull anyone's cluster for free.. I can do it in about 90 seconds now. sigh.

Thanks again, Brian and anyone else who may chime in.

Best to all,

Barry
 
#9 ·
1. The Bentley manual shows the pins on the voltage regulator backwards from what I believe is the standard VR configuration. Brian, you mentioned something similar in one of the threads you linked for me. I thought that the pins were as follows, referring to the pins with the pins facing downward and the metal back of the VR facing away from you.. Left pin is input, center pin is ground, and right pin is stabilized output. The Bentley reverses the input and output pins, with the stabilized voltage present on the left pin. Which is correct?

The Bentley shows proper voltage. The 9V is incorrect. All the ones that I have seen are lm7810 versions.... The errata sheet from the vendor appears to be incorrect. The voltages I measured on pin1 to 2, then 2 to 3 are correct according to the Bentley.


2. Could a 9V regulator cause all the weirdness I'm still experiencing? Like I said, the gauges seem to move fine, but I just can't get them to stay on. No amount of wire or contact wiggling seems to make a difference.

YES.

3. Is the full-scale temp indication prior to engine start a standard thing for the temp gauge?
NO

4. If (shudder) a new circuit board is needed (as the Bentley manual suggests as a solution to MANY problems with the gauges and indicator lights, most of which I've experienced), are they available? I can't find them online. I have an '82 Rabbit convertible.

It is easier to source a complete instrument cluster off of ebay, thesamba.com, vwvortex.com They run about 50 bucks usually.

I know I had to buy one once, then roll the Mileage to the proper position.
 
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