| Author | Message | ||
     Randy Roberson Frequent User Username: wascator Post Number: 878 Registered: 05-2009 |
Hi, everyone! I’m finally getting around to getting the ‘77 going. Three issues: the first is, when I connect the (known good) battery, the open door and interior lights and the headlamps work, but upon turning the key on nothing in the instrument panel powers up and the starter is unresponsive. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 3341 Registered: 06-2009 |
Check your starter relay, for starters (no pun intended, and there are inexpensive replacements you can acquire for testing, even if you want to go original afterward if that turns out to be the issue, or an issue). Brian | ||
| Randy Roberson Frequent User Username: wascator Post Number: 879 Registered: 05-2009 |
OK thanks | ||
| Randy Roberson Frequent User Username: wascator Post Number: 880 Registered: 05-2009 |
It occurred to me that, as there is no power to anything involving turning the key switch, power is out upstream of the starter relay. I am studying the wiring diagram and will start looking at the power wiring to the switch box. | ||
| Randy Roberson Frequent User Username: wascator Post Number: 881 Registered: 05-2009 |
As I have 12 V at the starter solenoid main terminal, I am suspecting the ammeter shunt; more later. I cleaned the shift contacts on the steering column and the shift motor seems to be responding as intended afterward. | ||
| Randy Roberson Frequent User Username: wascator Post Number: 882 Registered: 05-2009 |
I hard-rock-mined my way in to the ammeter shunt; I used my meter to find 12 Volts at the larger brown wire. I presume this wire comes from the 12 Volt terminal at the starter. I tested resistance between any two of the four copper terminals on the shunt and did not find an open circuit; there was measurable resistance. I am unsure if I can jumper from, say, the large brown wire to the similar-size brown/white stripe wire, without risking damaging the ammeter or something else | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 3342 Registered: 06-2009 |
Randy, I know that Geoff Wootton (Dounraey - here and on rollsroyceforums.com) once configured his Shadow I to start with the flick of a literal switch under the hood/bonnet. He may be able to help you out with this one. Brian | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 2342 Registered: 05-2012 |
Hi Brian, Hi Randy I'm, afraid I can't help. I'm only familiar with my "Series 1" car (1974). I've learned not to comment on Series 2 cars as there are so many detail changes, but in any case I'm sure Randy is far more proficient than I when it comes to investigating wiring problems. Regards my under hood starter button and safety switch, yes I fitted them after I nearly got stuck 40 miles from home when the starter would not crank the engine. It was only by luck that the engine did start, after the hundredth attempt. As I recall I wired the switch from the positive side of the starter motor to the starter solenoid.  | ||
| Randy Roberson Frequent User Username: wascator Post Number: 883 Registered: 05-2009 |
Great; all input is appreciated, plus it’s great to be able to ask questions and discuss cars with like-minded people from all over! As for my Car: I have verified that I have power to the switch box: + 12 Volts to the large wire, brown with white stripe, so I know the Ammeter shunt is not bad. My Car’s headlamps and interior lights work normally, but anything that powers up when the key switch is turned to ON or START is dead. Gearbox selector works when the key is On; no horn nor anything else. I have the switchbox out; as much as I can see is about as clean and pristine as it would be when new. I see no loose, broken, or corroded parts. As I understand more completely how it works; the sequence of events when the key is turned to ON then START, I will progress more. I suppose I am like most amateurs: I hope someone will read this who has encountered the same issue and so can say, “Here is the problem..” then I will have a target at which to aim. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 3343 Registered: 06-2009 |
Randy Roberson wrote: I hope someone will read this who has encountered the same issue and so can say, “Here is the problem..” then I will have a target at which to aim. We all hope for that little miracle. And on more than one occasion it has occurred for me (and I believe I've made it occur for others). When it comes to electrical stuff, though, that bolt of lightning isn't likely to originate with me! Brian | ||
| Randy Roberson Frequent User Username: wascator Post Number: 884 Registered: 05-2009 |
I looked in the rear of the switchbox; identified the little copper wiper strips; none are broken nor corroded, all seem to be making contact as intended. I know the transmission selector only operates with the key switch ON, and mine works, but far as I can tell, that is the only “key ON” item that powers up. | ||
| Geoff Wootton Grand Master Username: dounraey Post Number: 2343 Registered: 05-2012 |
Randy I once tried to start my car with the alternator disconnected. It wouldn't even crank the engine. I would check all the connections to your alternator and regulator to rule this out. | ||
| Randy Roberson Frequent User Username: wascator Post Number: 885 Registered: 05-2009 |
In my case the issue is not only cranking/ starting; the instrument panel won’t even power up when the key is turned to ON. The headlamps and interior lamps; underbonnet and boot lamps work, and the shift positioner works with the key switch ON, as it should. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 3344 Registered: 06-2009 |
Randy, Check all the grounds that attach from the instrument panel to the metal frame. I once had the entire lower part of the instrument panel (right above the knee roll) suddenly spring back to life right after I cleaned up the ground connections and treated them with electrically conductive grease before putting them back together. It's remained functional since. Brian | ||
| Alan Dibley Frequent User Username: alsdibley Post Number: 387 Registered: 10-2009 |
When I got my Bentley T many years ago I traced an electrical gremlin to a bad connection in a toe-board connector (green crud corrosion). I pulled all the engine-side connectors and cleaned and greased them. I also found one blade that had completely corroded through - what circuit was affected I didn't bother to find out - it wasn't the one I was looking for. There was a spare pin in this case so the repair was simple, except for access to the cabin side to swap that one (with an explanatory label on the wire). Since then there have been no "difficult" problems with electrics - thankful for that, the circuit diagrams are not the best. Some of these connectors have PERMANENT 12VOLTS so any moisture in the engine compartment is trouble, and it rains occasionally in Somerset. Alan D. | ||
| AdrianJ Unregistered guest Posted From: 146.200.18.75 |
I had a similar issue some years ago on a '78 Wraith. Turning the ignition on failed to illuminate the switchbox lights, headlight switch worked fine powering the headlights as you experience. I removed the switchbox, at the rear was a yellow insulated copper strip. It's function is to take power from the 'Lights' side of the switchbox to the 'Ignition' side, i.e power goes into the 'Lights' side first then bridges across to the 'Ignition' side. Checking for continuity across both ends of that copper strip (sheathed in yellow insulation) showed open circuit. I was able to withdraw each end of the copper strip from the yellow insulating sleeve. The strip had fractured inside. I don't believe a failed ammeter shunt will prevent the car starting. My Shadow 11 had a non functioning ammeter, the shunt had failed, car still performed o.k. I replaced the shunt to restore a functioning ammeter. (Message approved by david_gore) | ||
| Randy Roberson Frequent User Username: wascator Post Number: 886 Registered: 05-2009 |
Hi, Adrian, I see that strip; I will put the meter probes on it soon as I return from the swap meet at Hershey PA. That would definitely cause the issue I have. I know I have + 12 Volts to the switchbox and the headlights work perfectly. | ||
| Randy Roberson Frequent User Username: wascator Post Number: 887 Registered: 05-2009 |
Back from the AACA Hershey swap meet; put the meter on the yellow-insulated strip and no continuity. Hummm; | ||
| Randy Roberson Frequent User Username: wascator Post Number: 888 Registered: 05-2009 |
I can buy the electrical link from Flying Spares at a very reasonable cost. Now to figure out how to get the switchbox apart and reassembled/ installed… | ||
| Randy Roberson Frequent User Username: wascator Post Number: 889 Registered: 05-2009 |
Photo of the failed part; it is cleanly broken at a sharp bend within the yellow insulation. I am reassembled and checking the wiring diagrams to get the wires reattached properly.  . | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 3347 Registered: 06-2009 |
Randy, If you can post a couple of additional photos, particularly of that part in situ, it would be very, very helpful to future readers. It's really handy to be able to see how/where a given thing fits into "the puzzle" that are certain aspects of these cars. The switch box is definitely of puzzle class. Brian | ||
| AdrianJ Unregistered guest Posted From: 146.200.18.75 |
That is exactly what I experienced and in the same place too. Clearly not an isolated incident. Repeated heating / cooling caused by current draw the possible problem? Pleased you resolved your issue :-) (Message approved by david_gore) | ||
| Philip Sproston New User Username: phil2025 Post Number: 47 Registered: 07-2006 |
I had the same bar brake in SS 1973 car would stop when it felt like it when on for 3 years when it broke and stop the car l found the bar had a fault under the yellow cover in it from the factory. | ||
| Randy Roberson Frequent User Username: wascator Post Number: 890 Registered: 05-2009 |
Here is the best photo I have of the rear of the 1977 USA model switchbox; one can discern the squarish yellow insulation on the brass bar. My advice is: once you get the switchbox out of the dash, remove the metal ring but do not start removing any wires you don’t have to. Find the squarish bar with yellow insulation, then locate the two ends and test end to end with an ohm meter for continuity. The brass bar is rather stiff and is torturously bent to get the two ends at Point A and Point B. There is a sharp bend underneath the yellow insulation hearer one end and that seems to be where it tends to break. When you get the ends loose you will be loosening little wiper-connectors on each end, so pay attention so you can get them back in place. Take photos before so you will have references to help get everything back in the right place. With care it’s not that difficult.  . | ||
| Randy Roberson Frequent User Username: wascator Post Number: 891 Registered: 05-2009 |
As has been noted in above posts, the problem could well be intermittent. Because the bar is stiff it well may not appear loose. I suggest testing for continuity while stressing it around the center to see if you can make it act up. | ||
| Randy Roberson Frequent User Username: wascator Post Number: 892 Registered: 05-2009 |
Anyone know the identity of the small lamp bulb for the oil pressure warning lamp on the switchbox? I need one. |
