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Hello, and help please

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Valkster

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Hello, my name is Mark Valk. I am currently restoring an '80 model Spitfire and driving a '78. The '78 recently started losing power to the instruments. The problem is intermittant. Sometimes they work for 10 minutes of driving before failing, sometimes they don't work at all when I start the car. The odd thing is that if the gauges are working (tach, fuel, and temp) and I turn on my signal lights, they all fail abruptly. Any suggestions or where to start would be appreciated. I have checked/cleaned all contacts I can find but am not sure what the next step is. Thanks,
Mark
 
Just to state the obvious - did you check the ground wires for shorts?
 
Thank you for your reply...I am a little unsure what you meant by checking the ground wires for "shorts". I always thought (maybe incorrectly) that a short was an undesired path from a positive source to ground...a closed circuit. However, I have checked each ground connection I could find and cleaned it with contact cleaner and made sure that each connection was secure. If you are asking if I have checked ground connections for shorts to a positive power supply or device, then no I haven't. Where does that sort of thing typically occur and how would I find them...while cleaning the grounds I did not find any terminals touching each other that shouldn't be. Still, there has to be one somewhere, or a loose ground I haven't found. After the ground connections at each gauge and tail light is verified, what should be my next place to check? Is there a main grounding terminal under the dash or could a bad voltage stabilizer cause this? Would a faulty ignition switch, or blinker assembly, cause this behavior? I appologize, I should have stated my initial question clearer. Oh, even though I lose all electrical gauges and blinkers when the problem occurs, I do still have headlights and my hazard lights do still blink when I turn them on. Hope this helps, thanks in advance for any help.

Mark
 
Apologies Mark,

I actually meant when I started typing an open circuit - a loose ground or a broken cable. Type in haste repent at leisure...

Based on the diagrams - like this one (click on stock schematics) - https://www.advanceautowire.com/

it doesn't look like they go through a common ground point, but they DO all seem to go through the pot on the dash from a common fuse. I'd grab a multimeter and wait until the next time you have a problem then see how far you can get down the wiring and still have 12v.

The intermittent nature of the problem would tend to indicate a dodgy connection somewhere. You will notice from the diagram that the lights all come from the same fuse, and the rears share a connection for some of the way. If these are all good (or bad for that matter) then it might enable you to eliminate/include some possibilities. Check these out too - especially since you say it happens when you hit the signals.

Good luck - electrics are just the worst pita...
Once again apologies for the confusion from my shoddy typing.
 
Just a few thoughts (possibly incorrect I might add). When you turn on the turn signal, other electrics fade... could the alternator/generator be failing. Also, I have only had a TR3 (and MGA same era), but it seems that the voltage regulator on the firewall was usually the culprit for improper electrical feeds being sent to certain areas, as well as the corrosion factor at those ground/live wire connections. There is a product, I'll post the name later, that you can add to the bare wires and connector points that keeps a clean connection. I would suggest having your battery and charging system checked for free at a chain auto store, then checking into the voltage reg. (could be the Lucas type black box on the firewall). If all else fails blame it on the gremlins... /ubbthreads/images/graemlins/wink.gif
You'll find the source if you follow the test light advice above for sure.
Hope this helps, sorry if I'm wrong about the Voltage Reg. on your car.

Brian /ubbthreads/images/graemlins/cheers.gif
 
Something just dawned on me... you turn your turn signal on and they all fail? Could your turn signal (trafficator) be defective and drawing all the current? Not sure where it is located, but you may want to replace it or at least check voltage and connections on it while you're doing all the other tests. Check the Moss catalogue for location and price a new one. They are called "trafficators" on the older Triumphs and are fairly reasonable, they control the juice to make the turn lights blink properly....

Brian
 
95% of the time when you see these symptoms, it is a dirty connection, usually a bad ground.

Did you check the ground strap from the battery to the body? What about from the engine to the body? What happens is the poor connection can support the amperage necessary for the gauges, but when the signals come on, you are actually powering serveral lights, and the voltage drop over teh bad connection is so great that nothing works well..

Does this ONLY happen when the turn signals are operated? What about the hazards? or other dash components? If it were the regulator/alternator, then anything, especially the headlights, would cause this failure..

I'm going with a bad ground..

:smile:

Good Luck
 
Sorry for the delay, work you know. Thanks for all the replies. The problem is not isolated to when the turn signal is used. The gauges sometimes fail without any "power consumer" being activated. Also, when the failure occurs and the signal lights are not working I still can get the actual bulbs to come on with the hazard switch. The headlights seem to work fine, too, whether my gauges/blinkers are working or not. Just to throw this in, the horns only work sometimes and I am getting voltage to them...My windshield wipers worked last week and they, too, have now failed. I had thought about the voltage stabilizer (the small device attached to the back of the speedo) being a problem. Unless I am mistaken the newer Spits like mine do not have voltage regulators like the older generator-equiped cars. Oh, as for location, I live in Greeneville...small town between Knoxville and Johnson City. Thanks again for all the pointers, I'll post the solution when I figure it out.

Mark
 
Understandable confusion of terms here. Your Spitfire does indeed have a voltage REGULATOR, but it is built into the Lucas alternator; it's not separate as it was on the older generator-equipped cars. Meanwhile, the voltage STABILIZER is there for the sole purpose of providing a more or less constant 10v or so to the gauges, the idea being to avoid the bouncing needles of the older unstabilized gauges. That likely has nothing at all to do with any other electrical problems you're seeing.

In your case, I'd look carefully at any and all contacts in and around the fuse box, as well as any grounding points on the affected accessories. Oh, and be sure that all the major power cables to battery, ground, etc., have good CLEAN contact surfaces and are tightened down as appropriate.

Never mind all the silly Lucas jokes; odds are that your problem is either a dirty or loose contact...or both.
 
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