In a message dated 98-05-26 11:12:50 EDT, tom.w.wagner@Central.Sun.COM writes:
> When I turn on my headlights I have no turn
> signals(left or right), but when the parking
> lights are on or the headlights and parking
> lights are off - all is fine.
>
> Can someone help me in where I need to start
> looking at???
>
> I hope it is not a ground, cause then I am
> lost as to where to go.
Tom,
I think you're safe as for as a bad ground goes. I'm reasonably certain it is
not a bad ground, although that could be a contributing factor. The reason I
say it is not a bad ground is because the only common ground between the
lights and the turn signals are the front parking/signal lamps. Since the
turn signals work whether or not the parking lights are on says that the
common ground here is not the problem.
My best guess is a faulty connection in the main power feed to the head lamp
switch and the ignition switch. If you trace the power from the
battery/alternator, you will find it goes first to the ammeter, then to the
ignition switch. From the ignition switch, power is jumpered to the headlight
switch, and through the ignition switch to the turn signal switch. The only
commonality in the TS circuit and the headlight circuit is the power feed.
Turn signals are very sensitive to voltage drops in the wiring. If there is a
bad connection in the power feed described above, the low current draw of the
parking lights may not drop the voltage across the bad connection enough to
cause a problem, but the high current draw of the headlights will.
When I said a bad ground is not the problem, but may be a contributing factor,
that is because the ground is good enough for the turn signals as long as the
voltage is high enough. The voltage might not be dropped enough to cause a
problem if the grounds were good, but coupled with a bad ground, the
combination may more than the turn signals can deal with. It's also possible
that there are other bad connections in the TS circuit that, by themselves,
would not be a problem -- only when combined with the low voltage from the
power feed.
Check and clean the connections in the power feed circuit, and I think your
problem will go away. You will probably do yourself a favor if you check all
the wiring in the TS circuit as well.
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://www.sky.net/~boballen/mg/Masters/
'74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
'68 MGBGT---organ donor for the '74
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