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blackcreek
06-28-2010, 08:40 PM
I have a 97 prostar that has never had the volt meter read correctly. Finally got around to reading out the voltages and found out the low readings in comparison to direct readings at the battery were due to corrosion and the actual build of the wiring harness.
I fixed the reading by adding a direct wire from the key on power post and running it directly to the volt meter. This bypasses about 10 or so daisy chain connections that power all the gauges from one 12 volt feed wire. You also have the choice of bypassing the safety switch at this point also.

I started by checking voltage at the ignition switch by turning the key on and checking voltage at terminal B. It read 12.5 at the terminal and 12.6 at the battery posts , only a 1/10 volt drop so wiring from the battery was good. Next I checked the reading at the volt meter and only got 11 volts. that is a 1.5 volt drop across all the instrument connections.
Terminal A is hot battery power
Terminal B is key on power
Terminal C is aux power position (I took off wire for better picture)
Terminal D power for starter
*Note this is not an original ignition yours may differ slightly.
http://i91.photobucket.com/albums/k304/blackcreek123/PICT2833.jpg
The red wire my finger is touching is the wire I added, the purple wire powers all the instruments with a 12 volt feed.


The next picture shows the back of the volt,temp, and oil pressure gauges. The purple wire runs through the safety switch at some point and then gets daisy chained all over the instrument panel. These are just some of the multiple connections which finally end at the volt meter. Each connection is getting old and slightly corroded so by the time it gets to the volt meter the reading is way off.
http://i91.photobucket.com/albums/k304/blackcreek123/PICT2836-1.jpg

The last picture shows the back of the volt meter and the other end of the red wire I added. The grounds were much bigger wires and seemed to be up to the task even after 13 years. ***Note*** If you want to bypass your safety switch operation leave the purple wire and new red wire attached to the volt meter. To retain the saftey switch operation simply remove the purple wire from the back of the volt meter and tape over the exposed connector or simply remove the short purple jumper wire from the oil pressure and volt meter gauges.
http://i91.photobucket.com/albums/k304/blackcreek123/PICT2835.jpg

After adding the wire the volt meter now reads within 1/10 volt of battery posts when running and I now show 13.5 volts at idle. The oil and temp gauges also read slightly different and I am sure are more accurate due to the correct 12 volts reaching the instrument pod.
http://i91.photobucket.com/albums/k304/blackcreek123/PICT2843.jpg

I had to reach around inside the panel to snake the wire through some holes to reach the other side. You just need to search for a way to run the wire but it is not too bad.
If you want your readings to be correct I highly recommend this fix, now I can tell if my battery or alternator are really having problems instead of guessing.

Footin
06-28-2010, 09:08 PM
Nice write up, I did the exact same thing last year but I also ran another wire to the tach so my Perfect Pass would not detect low voltage.

You have also done something else that you may not realize, you have eliminated your kill switch. I am not sure how, but mine did not work after I made these same changes.

blackcreek
06-28-2010, 10:00 PM
See next post

blackcreek
07-04-2010, 11:12 AM
Thanks Footin. Finally got everything sorted on the back of the panel. I updated the instruction to include the option of bypassing the safety lanyard or not. If you want correct voltage readings and kill switch operation run the red jumper wire and remove the short purple jumper. For optional safety switch bypass leave the purple and new jumper connected. Your choice, I tested in both configurations to make sure.

east tx skier
07-04-2010, 11:41 AM
Nice write up, I did the exact same thing last year but I also ran another wire to the tach so my Perfect Pass would not detect low voltage.

You have also done something else that you may not realize, you have eliminated your kill switch. I am not sure how, but mine did not work after I made these same changes.


If you are running an older version of Perfect Pass, not allowing it to detect a drop in voltage could cause it not to save changes. A drop in voltage was, until about April 2008, the way PP knew to quickly save, ie when you turn of the ignition. Nowadays, it saves changes 5 seconds after they are made.

pitpro
08-02-2011, 04:57 PM
If you are running an older version of Perfect Pass, not allowing it to detect a drop in voltage could cause it not to save changes. A drop in voltage was, until about April 2008, the way PP knew to quickly save, ie when you turn of the ignition. Nowadays, it saves changes 5 seconds after they are made.


Here's my setup. 1996 Prostar 205. I have the old PerfectPass and my gauges are laid out differently. I thought maybe I could disassemble all the connections, clean and reassemble and have the correct voltage show on the gauge. Cleaned them all and it didn't help. So here is my question: There is a red wire with a white stripe
that is not connected to anything behind the Fuel and voltmeter. (see picture)From the pictures of the OP, the Red wire with white stripe is Hot, on "Key on" side of ignition. Do you think this wire behind the Fuel/Voltmeter is also hot, contolled by "Key on" side of ignition? Could the fix be this simple? Disconnect the purple jumper completely, and hook up the red wire with the white stripe?
If this won't work, what is that Red wire with the White stripe for?
Also, am I correct that the jumper wire needs to come off if I have the old PerfectPass to prevent constant power to the PerfectPass, not allowing the PP to sense volt drop, therfore no saved settings?
Thanks for any help you can provide!!
John
http://i1142.photobucket.com/albums/n620/pitpro1/b9ba053c.jpg
http://i1142.photobucket.com/albums/n620/pitpro1/05958375.jpg
http://i1142.photobucket.com/albums/n620/pitpro1/b0c4c757.jpg

Table Rocker
08-02-2011, 06:20 PM
You need to check and see when that wire is hot. The first thing, if it is ever hot it should be connected to where it belongs or taped off.

I have a '96 205, and on my boat there is a clock on the left and the voltage gauge is on the right. (I don't have perfect pass). I would suspect that the red with the white stripe might be an always hot lead for the clock.

Good luck in that bowl of spaghetti, but be sure and tape it off if it is ever hot and not used.

Ski-me
05-18-2013, 07:31 PM
Bump....

I just tried this and it looks like I'm now getting a much better reading. thanks for the great write-up!