on a 1990 cabriolet , does the inside cluster temp gauge needle move from left to right or...

[stronglikebull]

right to left as it gets hotter. i'm asking b/c i've seen some videos where it looks like the temp gauge needle is on the left side, then moves to the right as the engine gets warmer. ours starts on the right and moves left as the engine gets warmer. is ours wire backward or something?

[CajunSpike]

On all 3 cabbies I have, cold is to the drivers left hand....hot is to the drivers right hand..facing the gauge, sitting in the drivers seat.

[stronglikebull]

On all 3 cabbies I have, cold is to the drivers left hand....hot is to the drivers right hand..facing the gauge, sitting in the drivers seat.

ok, wow. um, ours is exactly the opposite. ours starts out on the right and as the engine gets warmer, it moves to the left. so my question is, can it be wired backward or is there any explanation for this?

[CajunSpike]

The answer to that will have to come from somebody else.

[briano1234]

Let me ask, does the gauge read hot on the left or the right?

If the needle goes full right that usually means that the gauge is getting full power to the needle, then as the car warms up, you are getting a stabilized voltage. The sender or Low level coolant relay / voltage stabilizer can cause this so we need to eliminate them and finger what is wrong.

If the gauge reads hot on the left, then running backwards makes sense.

But aslo if the Gauge reads hot on the left it isn't the proper gauge.


If the gauge reads cold on the left and hot on the right, then is your fuel gauge working correctly, as well?

Because the 10V Stabilizer sounds as if it is bad we will test for it.

The Water gauge is biased from the 10V stabilizer, and it in conjunction with the Sensor (black one on the water outlet flange) works together.

Take a 9V dc battery with 2 wires off the posts.

Remove the water temp sender connector, black one under the hood.
Place the Positive on the yellow/red wire and the negative on the brown.
Go look at your meter, it should be 3/4 to full hot. Leave it connected this way for a few minutes... It should also go from left to right and hold.

If it does, then you have a bad sender on the water outlet flange, replace it.

If not, then you have a gauge issue / voltage stabilizer / relay issue even if the gauge goes full hot, but then gradually returns to 0 it is flaky, and needs to be replaced or repaired.

If you have a Genuine VW radio be sure you have the radio codes.

Disconnect the battery ground

Take the fascia off, and disconnect the speedometer cable from the back of the cluster.
LEAVE THE OTHER CONNECTORS ON.

Shield the 4-way bare wires with electrical tape so you don't blow a fuse or burn the wires.

reconnect the battery

Key in and in the run (NOT START) position.

IF the Gauge goes immediately to the right, then measure the voltage on the gauge at the 2 nuts. it should be @ 0Vdc.

IF if isn't as I suspect, then you need to go to the Voltage Stabilizer.


pin2 is ground
Pin3 is 12.5v after start 13.75v
Pin1 is 8V after start 9.9V

You don't need to start the car You need the static voltages. Are they correct?
Start the car, are the voltages now higher? if so then the voltage stabilizer is good.

Replace the gauge.

The internals of the gauge act like a toaster.
As the current builds up, it causes a nicachrome wire to heat up and bend the needle.



There are a couple of solder joints, that can "cold" solder and act the ass, but I have never seen them on mine act the way you describe.

So I would replace the relay first, then attack the gauge.

How to repair flaky water gauges?



Temp gauges are somewhat temperamental.
They can go out, or intermittent, and lets face it
It is a really great gauge to have working.

Here are the common causes that I have found.
and the fix's.

Take the cluster out of the dash

Test it apply 9vdc to the back, the negative lead is
on the right, Positive is on the big left stud.



Does the meter deflect, leave it on a bit... does it finally die? intermittent connection.
Take the nuts off the studs, and clean the corrosion off of them retighten the nuts.
Does the meter deflect and stay? Good job, your done put it back in the dash.

Still not deflecting or intermittent?


Remove the large connector from the bottom of the cluster and
carefully remove the mylar off the tab.



Remove the light bulbs for the cluster display and
gingerly remove the mylar off the locater pins.







Remove the 8 screws that attach the cluster to the face plate.


Remove the voltage stabilizer.




The Phenolic washer is on the bottom screw next to the speedo





Carefully separate the Cluster back from the Cluster front.

Remove the 3 nuts on the back of the water gauge.

Carefully tap the gauge out of the assembly by lightly
tapping on the studs. Once the gauge is out, place the
remaining cluster assembly aside.




Here is the gauge This is out of a jetta.



Apply voltage to it to see if it deflects.



If you are very careful you don't have to remove the needle, but you have to
be careful on the next step in removing the rivets.

Carefully remove the needle from the two wires that are holding it.



The Gauge face is help by 2 brass rivets.



File them flush with the base plate, then pry them out from the front by inserting
a small straight slot between the face plate and the Base..







With the Face plate off, you will see either this:



or



Look at the thing, it is basically a toaster. It uses Nicachrome wire wrapped around
a bi-metalic spring, so as current passes from the sending unit to the gauge it causes
the wire to heat up, and move so that it will make the needle deflect.

Because of the nature of the wire it really should of been spot welded or silver soldered to the
connection points, as the wire gets older it will heat all the way back to the connections
causing corrosion and a cold solder joint. This cold solder joint and corrosion is
what causes the gauge to stop working. So we have to fix it.



Shows the 3 places that I have found to be where the connections have issues.

Using a de-soldering tool remove the globbered solder from the attachment points





Carefully scrape the wires with a Xacto, hard to photo while doing. This will remove the corrosion
off the wire.

Now make sure that the wire is fully attached to the studs or solder points.

Applying heat, and solder let it flow, the Studs will get hotter than blue blazes.

As soon as the wire is taking heat and solder give it another few seconds.....

Then remove the heat and cool it by taking a wet rag and touching it to the studs....This will
Quench the heat and stop a cold solder joint.

Now test it.

Apply voltage to the pins does the arm move... yes/no.... if yes you are done, if no apply more
heat and solder. Test it..... till it is correct.

Mix up a tad of Jb-weld and apply it to where the brass rivets were and glue the face plate to the
body.

Reattach the needle if you removed it.

Reassemble the gauge in the cluster assembly.

Now is the time to think about a couple of upgrades.

1. Replacing the light bulbs. I use sockets from a Isuzu, Pathfinder or Saturn, with removable
bulbs, I go to the parts store and buy "warning lights" (higher wattage) and replave the bulb. You need
3 of them.

I trim the Detent stop with a knife. Spring the brass pads out a bit.



Now, cafully look at the cluster and "pop" the bulb holder off, it is Heat welded to the
case. Remove the crappy green film. and replace the cover and either melt it back or
Jb-weld it.

Carefully reassemble the cluster front to the back.....
Reinsert the screws.
Reinsert the voltage stabilizer.
Place the mylar over the pins and insert the light bulbs and twist.
Apply voltage to the mylar at the bulbs and make sure they light...if not you
may have to twist them more...Carefully... be gentle.

Now before replacing the big connector. Apply a piece of Electrical tape to the
Pin side of the tab...



Wrap the mylar and replace the connector shell.

Now the last upgrade...... Tie a new ground wire from the chassis to the
large cluster connector (the brown wire). I usually screw a 12 inch wire to the
frame with a self tapping screw after drilling a small pilot hole.
Splice it in to the cluster wire. Heat Shrink or tape the connection.

Enjoy a working gauge........better lighting, and a less flaky cluster.


Did you think any answer from me was gonna be easy?

[rabbitnothopper]

briano, you should get paid to post that kind of epic response

but atleast vwvortex appreciates your efforts!

thats great information and highly over the top for most tinkerers


for most people after the step of removing the gauge its just time to replace it instead of fix it

[DarthVW]

briano, you should get paid to post that kind of epic response

b

Exactly, what would we do without Briano knowledge here....
I think he is the real Dos Equis XX guy.

[YJSAABMAN]

Exactly, what would we do without Briano knowledge here....
I think he is the real Dos Equis XX guy.

briano1234: "The most Cabbiest man in the world!"

[stronglikebull]

i've been out of town for the last few days and just got back in. brian, just wow. what a response. the poster who said it might be over most folks heads is definitely including me. but i will tackle (maybe not today, but i eventually will tackle it using this response.

to answer your first basic question though:
"Let me ask, does the gauge read hot on the left or the right?"
as the engine gets hotter the needle moves to the left as you are looking at it from the driver seat. i dont know if this matters or not, but it also drops back down after get almost to the left (where the little light is in the gauge that lights up if the car overheats). i guess the fan comes on and cools the engine down. the gauge needle then moves back to the right. and it continues this pattern as i drive it. it moves to the left as the engine gets warmer then moves back to the right.

[stronglikebull]

maybe i should try to take a video of all of this if it will be helpful...

[stronglikebull]

also, brian, the fuel gauge is working properly.