I have a 69 Roadrunner that I am restoring. I have replaced the circuit board, rebuilt the tach, and put 12 volts to all of the gauges, and they all worked. When I installed the dash, nothing works, except the washer pump and parking lights. Am I missing some ground wires somewhere? Any help would be greatly appreciated.Jim
perhaps this will help...
see the TWO mounting screw holes at the bottom of the circuit board..please create a short wiring harness with 3 ring terminals in a Y shape..so you have a ring terminal on the 2 positions on the circuit board bottom...and the third one on a ground connection under the dash... first pin on the left is dash lightingsecond pin from the left is 12 volts to the instrument cluster voltage regulator.the instrument cluster voltage regulator pulses around 5 volts to the gauge wiring across the top row of the circuit board.the right 3 pins comes from the various gauge senders..but thats only half the circuit.. the other side is the ground.. ~~~~~~~~~~~~~~please also verify under the hood... that your grounds are intact..this should be printable.. verifies the ground connections under the hood..please verify that you also have a braided ground strap from the back of the cylinder head/s to the ignition module mounting screws on the firewall...this will make your modules live much longer..post results.. by number1...2..3..4..
Thanks for the help. I'll give this a try.
Hi,does it matter if my circuit board is different than the one shown?
theory is the same....are you getting pulsed voltage to the gauges????
Hi, I tried the additional ground wire on the circuit board to no avail. Any other suggestions? I have not tested the voltage limiter as it is new.
check the connections between the voltage limiter and the circuit board...do you have your cluster out.. where you can photograph the back.. or even just tilted down.. where i can get an eyeball on the picture you take.. i don't have access to every car in the world to examine first hand for every issue..but i understand how all the circuits work...you could also have spread out female terminals in the circuit board connector.. is the voltage regulator as is shown above.. properly grounded ...does it have 12 volts to the middle terminal... does it put out pulsed voltage or reduced voltage???
I believe the limiter is in correctly. The cluster is not out, but I am considering removing the dash again. The voltage regulator is the same. It is putting out what appears to be reduced, varying voltage. Also, with car runing, the battery is only putting out 12.33 volts. If I take out the dash, I will send you some pics.
that's the charging system.. i have some info for you....see if you have power to the voltage regulator...i don't know which regulator you have.. the mechanical version that only had one wire to the alternator...or the electronic version. that has 2 wires..please..also check for voltage on the output terminal before you start any testing..what...yea...engine running.. digital volt meter hooked up to....battery negative to battery positive........battery negative to the alternator case...battery negative to the mounting foot of the voltage regulator...battery negative to the big stud on the starter relay...battery positive to the alternator output...battery positive to the blue wire on a electronic regulator..battery positive to the big stud on the starter relay...this will take you just a few minutes.. please copy and paste the info above.. and put numbers by end of each line...do you have a wiring diagram for your car..have you checked the electrical connector on the ignition switch.. that its not corroded...
why do i want you to run all those tests..i have found several failure places on various mopars..bulk head connectors. where the wire passes thru the bulk head..ignition switch connectors.. where the wires push on the back of the ignition switch and also the ignition switches..amp meter connections... and the amp meter... i have previously eliminated some of the amp meter issues.. buy REMOVING ONE nut that retained one of the two wires on the back of the amp meter.. pulling the wire with ring terminal off that stud and moving it over on top of the other stud.. on top of the nut.. then i put the first nut back on top of that stack.. this shortens the path thru the amp meter... and will get peoples cars running again when an amp meter blew up.. but not shorted to ground.. let me describe the positive side of the system..battery positive smaller wire to the threaded stud on the starter relay on the firewall... from there as a dark blue wire thru the bulk head connector but there is a fusible link in that part of the circuit... inside the car that wire becomes RED and goes to the amp meter..from the other side of the amp meter.. it comes off as black.. goes to a splice under the dash and feeds a whole bunch of stuff. but also continues back thru the bulk head connector and over to the alternator output stud ....