my 67 mustang gauges have started going out from time to time.  they work one time is start the car and the next time they don't. the clock does continue to work. the fuel, work temp, oil pressure and alt. gauges are the ones that don't work.  no other problems.  any ideas?  

This looks like a possible inst regulator (IR)issue since all of your gauges run off of 5v from it. But, before you chnage it out, try disconnecting and reconnecting the wires on the IR.  Also make sure yout IR is grounded properly and the inst pnl is also grounded.  Your ammeter comes dircectly from wiring attached to the solenoid (red) and the alternator (yellow) and typically the needles don't move much, so that's an unrelated issue.  

I have changed the IR and the gauges are fluttering and then they went out again.  i hit the gauge cluster and then then came back one. any ideas?  

The gauges are still going in and out.  it appears when i hit the horn several times,  the gauges come back on for a short time and then go out again.  also, sometimes the horn honks when i turn the wheel.  Need help!!!  

Jim, this isn't rocket science.  Take the inst panel out and clean the ground from the pnl to the IR. Also, make sure all of the wiring connections are tight and clean.  

Assuming a stock wheel, take the horn center pad off and inspect it for looseness replace whatever is worn out. You may need to pull the wheel and inspect the horn contacts also.  

Just had the same problem on my 67 while redoing the interior.  After much troubleshooting found the hot wire to the back of the fuse panel was loose.  tightened the connection up with needle nose pliars and have not had the problem since.  The inst. panel and transmision shifter light are on the same circuit.. The fuse panel comes off very easy, only two 5/16 bolts hold it on.  Good luck.  

I have checked the ground, the connections and back of the fuse box.  i did find a loose nut on the back of the ignition switch and thought that was it.  since he guages continued to work off and on, i decided to pull the ignition switch to check the wires, the switch came apart, i thought that was good until i replaced it and the guages did not stay on.  for the first 10 minutes of my drive, when they went off, the came back on when i hit the horn.  now they are not working at all.  any ideas???  

Is there a way you can put a volmeter probe or wire on the output of the IR while its doing it (maybe a short piece of wire that can be brought out from the dash) use the same ground point as the IR too.  If there's voltage all the time then it's in the wiring to the gauges or the gauges themselves.  

Thanks, i will try it this weekend hopefully.  i did just changed the oil and was checking for loose ground wires.  i did find what i think is the neurtal safety switch wires leaning up against the exhust pipe and it appears to have melted.    the wires come from the tail end of the transmission and plug into the fire wall on the driver's side.  do you think this could be the problem and is this the neutral safety switch?  

Jim, I would be suprised because the NSS circuit is only powered during start. However, the BU light circuit is always powered though the same plug (at least on my 66 NSS). After review of the wiring diagram I see the power source for the BU lights and the power source for the IR are right off of the same ign switch wire (black-green)and it's unfused. You may be on to something here.  Disconnect the NSS plug (with the black green wire in it)  from the firewall (with the engine running) and see if your gauges come back  

jlg, thanks for the help.  i did replace the NSS, trans. fluid had done some damage.  as for the gauges, i ended up replacing the IR again with a solid state one made in the USA which i got from auto instrument corp as the first one was from overseas and it did not hold up.  i do have a new posting about replacing or reworking my heads and sure would like your thoughts.