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1970 Indicator Fuse keep blowing

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sabre:
Sounds like an intermittent short. Do yourself a favour and make a diagnostic tool. Get a high wattage light (headlight or brake light) and solder 2 leads with aligator clips. Substitute the fuse with the light and start wiggling and switching. Should light dimly when indicators are on and bright when there is a short.

Matt G:
Thanks guys.  Loads of wisdom in there!  Flasher should be under the passenger dash according to my assembly manual.  I don't know if it's a moving issue (intermittent short), but that should be pretty easy to test.  Pulling the flasher is another pretty easy check.  No tilt steering, so there shouldn't be a pinch.  I love the idea of the light soldered in to the fuse panel to high"light" (heehee :grin:) the problem area.  Extremely logical and simple, yet still such a brilliant tool to help.
Thanks a bunch guys!

Matt G:
Hi guys, short update.
Flasher unit was buried up behind my passenger side cool air duct.  Pulled out and all okay, nothing popped.  I repositioned it to the top of my heater box so that it was a little more accessible.  I ran my indicators (with the motor off) for a while and started jiggling wires, turning steering, etc, etc and they were all good.  No issues found.  I thought that maybe my flasher may have been shorting on something in its old position, so I went for a drive again, and after the first use it was gone.
It doesn't seem to pop when I'm using it.  It cancels normally, etc, however the next time that I need to use it, there's nothing.  Hazards appear to be completely independent (but only tested while static).  It doesn't appear to be left or right hand turn dependent.
Next steps were going to be:
- turn on my left and leave it for a couple of hours to see  if it pops without any movement, engine heat, etc.
- repeat for the right
- Repeat with my hazards
If any of the above sets it off, then I'll replace the flasher units (I can't think of anything else that could cause it in this situation....)
- drop my steering, pull my instrument cluster and visually inspect all wires while using my indicators.
I thought more on the headlight scenario, and scared myself with some logic...  That being: If I'm popping fuses (pretty violent fuse wire burn on inspection of spent fuses), then if I allow that current to flow (through a headlight), I'd essentially be passing bucket loads of current through wires that my fuse is trying to protect.  I'm just a wee bit scared that dust, old wires, fibreglass and Murphy' law means that I stand a good chance of melting a wire in the wrong spot potentially giving my wife her corvette insurance money dream...
Feedback and ideas (as always) are really appreciated.

Vettech:
Just about to go for a late xmas lunch/tea, and have my internet back on line.

Questionsss.
1. Do you have cct diagram.
2. The fuse "NEVER" blows if using emergency flashers.
3. So car not butchered with LH/RH conversion.
4. You have not changed the flasher can.

I cant remember if this applies to 70 GM stuff, but the flasher may be the type that needs a level of load (current) flowing thru it to govern speed of flash etc.
Is the speed of indicator flash normal, does it speed up or down.
Since the E'flashers work fine, and in this mode all blinker lamps are flashed in unison, this mode represents max load thru the f/can.

If fuse ok in extented E'flasher mode then I would assess nil wrong with any indicator lamp wiring.

I would concentrate on cct in the dash and steer collumn.
Sorry have been told to get in car, by for now ......... cans are cheap!

Matt G:
Thanks Vettech, I appreciate the reply.
Answers:
1. Yes, but I appear to be lacking in skill. I'll try to read again tonight to see if I can figure it out.
2. Correct. Note that my e/flashers are on a different fuse AND on a different flasher (plugged above the fuse panel).
3. Correct. It's still left hand drive, however the wiring is messy, so I would think that some parts are clean and original, but I've worked through loads of really messy, non-original wiring, so I can't claim original wiring harnesses. I would think about 60% under the dash is original, now 85% under the hood, 95% at the rear and front.
4. No, I have not changed the flasher can for either the e/flashers, or indicators.

Indicator flasher does have a parallel resistor (or similar) on the mount for the flasher can.
Eflasher fuse is fine, however I have not taken a drive with the flashers on. I will try this to see if I blow the eflasher fuse.
Thanks again for the help.

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