One thing I don’t understand is how the light in the tachometer works. It looks like it has to ground through the “other” tail light/front marker light, which should make those lights blink as well.
I am wondering if that part of the circuit is correct?
The difference between the emergency flashers and turn signals is the number of bulbs. I would replace the flasher unit with an electronic one that does not depend on the current load to set flasher rate.
Rocky, yes the dash indicator light grounds through the opposite side front lamp.
Forest
Thanks, Forest.
The bulb in the tach will affect turn signal speed, but not emergency flasher speed. If there is an LED in the tach, one direction will flash faster than the other (and the tach LED won't work).
If the relay is current dependent, then it should flash faster in Emergency mode--since all bulbs are heating the relay faster.
At first I saw the 120 ohm resistor and the dimmer circuit and thought they'd be relevant, but as I see the switch drawn it simply shares the dimmer current to the lamp in the emergency switch until the switch is pressed...then the emergency lamp switches in unison with the external lamps--Lee
The bulb in the tach is not LED - its standard 2w incandescent. I'll do some checking on the left front ground and then plan to change out the flasher.
Doesn't the hazard run the same lights as the turn signal? There would be more bulbs in circuit (less resistance) on hazard in than when signaling, where there's just the front, rear, and 2w indicator in the tach. (I think I just restated what leea said).
Incidentally, I don't think my dash dimmer is doing anything at all.
..This has confused me about the discussion, because my experience was that a poor ground or open bulb created a slow blinker---since for thermostatic types of blinkers, the current draw heats the relay internally, causing the bimetallic to switch off...And this is just the opposite of what you are seeing, but no matter---if the blinker is looking for current, he's going to find more of it in Hazard mode. In my world, the hazard would be "On" for half the time as in turn-indicator, but the cool down-time of the bimetallic not change.
In my world of thermostatic blinkers, though, there is no ground at the blinker: bright bulbs everywhere are all that is needed, the only ground that matters is the ground at the bulbs (as these cause the current needed for the heater in the relay). This is the Mangusta and maybe early Pantera. But the new-fangled Pantera blinker shows a ground. So if its measuring current, well, could be that it is working just fine. If it is instead a simple timer (as I'd expect all modern blinker relays), only then is this a mystery !
At least from the schematic, the dimmer is irrelevant to the circuit when the hazard button is pressed; unpressed, the bulb in the dimmer switch is just following the other gauge bulbs, which won't have any power at all if the lights are off. When pushed, the bulb at the switch just becomes another load that affects the timing...and then only somewhat (its only the ant on the ant hill...)
My suggestion---don't press the hazard switch, and everything will be OK 
Lee
Solved - replaced driver footwell flasher with O'Reily's off the shelf EP35 flasher. Chased grounds, etc to no avail. The replacement package says "LED Compatible" - my bulbs are incandescent. The Tridon piece it replaced said "failure indicator". So I'm kind of cheating since the Tridon product sensed a failure somewhere (all bulbs working). The off the shelf version is evidently electronic and is not amperage dependent. So there may be a gremlin somewhere, but the fast blink is solved.
I have this same issue, chasing it now, My new to me car has fast flashing signals but normal hazard. My car has an EP36 electronic flasher installed, going to try the EP35 ,hopefully this works.
I had a fast blink problem as well that I was able to easily fix it thanks to guidance from John Buckman. I am not sure if this will help In my case the problem was a ground in the rear taillight area. Here is the thread and the fix.
EP35 signal relay fixed my issue.
