Have a good friend who has a 1966 GT-350 Hertz car. He has had continuing problems with his tachometer not working. He has had it completely serviced twice, and it will not work properly. He just took it all apart - again - to see if he could see what was up. Bench testing the tach, everything looked to be O.K. He checked the bulb and it was working. When he reassembled it, the bulb did NOT work. He understands that the tach grounds through the dash with the 2 screws that go through the vinyl and into the metal dash. Could it possibly be that that ground is not a good one? Anyone else had that problem? Would a discrete second ground wire work? Any help appreciated. Ron
I've had similar problems with mine - works intermittently, had it serviced to no avail. Interested in any results. At 11:35 AM 11/23/05, Ronald Robertson wrote: >Have a good friend who has a 1966 GT-350 Hertz car. He has had continuing >problems with his tachometer not working. He has had it completely >serviced twice, and it will not work properly. He just took it all apart - >again - to see if he could see what was up. Bench testing the tach, >everything looked to be O.K. He checked the bulb and it was working. When >he reassembled it, the bulb did NOT work. He understands that the tach >grounds through the dash with the 2 screws that go through the vinyl and >into the metal dash. Could it possibly be that that ground is not a good >one? Anyone else had that problem? Would a discrete second ground wire work? >Any help appreciated. >Ron > > >No virus found in this incoming message. >Checked by AVG Anti-Virus. >Version: 7.1.362 / Virus Database: 267.13.6/179 - Release Date: 11/23/05 Mike Greene www.gt350h.com 66 Shelby GT-350H 69 428SCJ Mach 1 70 Boss 302 70 351C 4 speed Mach 1 93 SVT Cobra 289 FIA Cobra Replica No virus found in this outgoing message. Checked by AVG Anti-Virus. Version: 7.1.362 / Virus Database: 267.13.6/179 - Release Date: 11/23/05
Ron- SInce no one else has replied, I'll give it a stab and let others more knowledgeable shoot me down. I'm working from memory here, mind you. The original Cobra Tach (Faria), has three leads, red, black & blue. The red and black go in series with the ignition and the blue is for the lamp. There may well be a ground thru the dash mounting screws...I've never seen a wiring diagram for these units. One simple way to check it is (knowing that there is a good bulb installed), run an external ground from the mounting base to a good ground, then turn on the lights and see if the tach lights up. If it doesn't, that shoots that theory in the head...unless there's a break in the lighting feed wire to the blue tach wire. That needs to be tested by unplugging the blue lead and testing the lighting feed wire with a test lamp to ground. Once that's solved, is the tach working? If not, I suspect there's an open somewhere in the circuit. It could be the pink wire feeding to the red wire on the tach. This is a ballast wire with a proper resistance to it. Check it for an open. Let me know how it goes and if anything I said helped. Regards, Stan ----- Original Message ----- From: Ronald Robertson To: Shelby Mustang Sent: Wednesday, November 23, 2005 12:35 PM Subject: 1966 GT-350 Have a good friend who has a 1966 GT-350 Hertz car. He has had continuing problems with his tachometer not working. He has had it completely serviced twice, and it will not work properly. He just took it all apart - again - to see if he could see what was up. Bench testing the tach, everything looked to be O.K. He checked the bulb and it was working. When he reassembled it, the bulb did NOT work. He understands that the tach grounds through the dash with the 2 screws that go through the vinyl and into the metal dash. Could it possibly be that that ground is not a good one? Anyone else had that problem? Would a discrete second ground wire work? Any help appreciated. Ron
Thanks, Stan. Will let you know how it goes. Ron ----- Original Message ----- From: STAN SIMM To: Ronald Robertson ; Shelby Mustang Sent: Wednesday, November 23, 2005 5:33 PM Subject: Re: 1966 GT-350 Ron- SInce no one else has replied, I'll give it a stab and let others more knowledgeable shoot me down. I'm working from memory here, mind you. The original Cobra Tach (Faria), has three leads, red, black & blue. The red and black go in series with the ignition and the blue is for the lamp. There may well be a ground thru the dash mounting screws...I've never seen a wiring diagram for these units. One simple way to check it is (knowing that there is a good bulb installed), run an external ground from the mounting base to a good ground, then turn on the lights and see if the tach lights up. If it doesn't, that shoots that theory in the head...unless there's a break in the lighting feed wire to the blue tach wire. That needs to be tested by unplugging the blue lead and testing the lighting feed wire with a test lamp to ground. Once that's solved, is the tach working? If not, I suspect there's an open somewhere in the circuit. It could be the pink wire feeding to the red wire on the tach. This is a ballast wire with a proper resistance to it. Check it for an open. Let me know how it goes and if anything I said helped. Regards, Stan ----- Original Message ----- From: Ronald Robertson To: Shelby Mustang Sent: Wednesday, November 23, 2005 12:35 PM Subject: 1966 GT-350 Have a good friend who has a 1966 GT-350 Hertz car. He has had continuing problems with his tachometer not working. He has had it completely serviced twice, and it will not work properly. He just took it all apart - again - to see if he could see what was up. Bench testing the tach, everything looked to be O.K. He checked the bulb and it was working. When he reassembled it, the bulb did NOT work. He understands that the tach grounds through the dash with the 2 screws that go through the vinyl and into the metal dash. Could it possibly be that that ground is not a good one? Anyone else had that problem? Would a discrete second ground wire work? Any help appreciated. Ron
Ron if it has pertronix ign it can cause the tach to be a little crazy ,the people rebuilding it needs to know if it has the pertronix .bob ----- Original Message ----- From: STAN SIMM To: Ronald Robertson ; Shelby Mustang Sent: Wednesday, November 23, 2005 2:33 PM Subject: Re: 1966 GT-350 Ron- SInce no one else has replied, I'll give it a stab and let others more knowledgeable shoot me down. I'm working from memory here, mind you. The original Cobra Tach (Faria), has three leads, red, black & blue. The red and black go in series with the ignition and the blue is for the lamp. There may well be a ground thru the dash mounting screws...I've never seen a wiring diagram for these units. One simple way to check it is (knowing that there is a good bulb installed), run an external ground from the mounting base to a good ground, then turn on the lights and see if the tach lights up. If it doesn't, that shoots that theory in the head...unless there's a break in the lighting feed wire to the blue tach wire. That needs to be tested by unplugging the blue lead and testing the lighting feed wire with a test lamp to ground. Once that's solved, is the tach working? If not, I suspect there's an open somewhere in the circuit. It could be the pink wire feeding to the red wire on the tach. This is a ballast wire with a proper resistance to it. Check it for an open. Let me know how it goes and if anything I said helped. Regards, Stan ----- Original Message ----- From: Ronald Robertson To: Shelby Mustang Sent: Wednesday, November 23, 2005 12:35 PM Subject: 1966 GT-350 Have a good friend who has a 1966 GT-350 Hertz car. He has had continuing problems with his tachometer not working. He has had it completely serviced twice, and it will not work properly. He just took it all apart - again - to see if he could see what was up. Bench testing the tach, everything looked to be O.K. He checked the bulb and it was working. When he reassembled it, the bulb did NOT work. He understands that the tach grounds through the dash with the 2 screws that go through the vinyl and into the metal dash. Could it possibly be that that ground is not a good one? Anyone else had that problem? Would a discrete second ground wire work? Any help appreciated. Ron
Bob: Had Pertronix and took it out. Went back to original points and condensor. Ron ----- Original Message ----- From: robert wolfe To: STAN SIMM ; Ronald Robertson ; Shelby Mustang Sent: Wednesday, November 23, 2005 7:55 PM Subject: Re: 1966 GT-350 Ron if it has pertronix ign it can cause the tach to be a little crazy ,the people rebuilding it needs to know if it has the pertronix ..bob ----- Original Message ----- From: STAN SIMM To: Ronald Robertson ; Shelby Mustang Sent: Wednesday, November 23, 2005 2:33 PM Subject: Re: 1966 GT-350 Ron- SInce no one else has replied, I'll give it a stab and let others more knowledgeable shoot me down. I'm working from memory here, mind you. The original Cobra Tach (Faria), has three leads, red, black & blue. The red and black go in series with the ignition and the blue is for the lamp. There may well be a ground thru the dash mounting screws...I've never seen a wiring diagram for these units. One simple way to check it is (knowing that there is a good bulb installed), run an external ground from the mounting base to a good ground, then turn on the lights and see if the tach lights up. If it doesn't, that shoots that theory in the head...unless there's a break in the lighting feed wire to the blue tach wire. That needs to be tested by unplugging the blue lead and testing the lighting feed wire with a test lamp to ground. Once that's solved, is the tach working? If not, I suspect there's an open somewhere in the circuit. It could be the pink wire feeding to the red wire on the tach. This is a ballast wire with a proper resistance to it. Check it for an open. Let me know how it goes and if anything I said helped. Regards, Stan ----- Original Message ----- From: Ronald Robertson To: Shelby Mustang Sent: Wednesday, November 23, 2005 12:35 PM Subject: 1966 GT-350 Have a good friend who has a 1966 GT-350 Hertz car. He has had continuing problems with his tachometer not working. He has had it completely serviced twice, and it will not work properly. He just took it all apart - again - to see if he could see what was up. Bench testing the tach, everything looked to be O.K. He checked the bulb and it was working. When he reassembled it, the bulb did NOT work. He understands that the tach grounds through the dash with the 2 screws that go through the vinyl and into the metal dash. Could it possibly be that that ground is not a good one? Anyone else had that problem? Would a discrete second ground wire work? Any help appreciated. Ron
