Old 6 volt auto headlight in series with 1154 on 12 volts

[John1397]

If one hooks a 1154 and an old 6 volt automotive headlamp in series and powers it with 12 volts will the headlamp being that it
is higher wattage cause all the current flow thru the smaller wattage bulb causing it to burn out?

 

[kuruman]

... will the headlamp being that it is higher wattage cause all the current flow thru ...

All the current? If they are in series, the same current flows through them.

 

[Asymptotic]

An 1154 lamp (I'm assuming this is what you mean by '1154') has two filaments. Which one of these are you referring to?
Sylvania specs - 16.8W/5.3W, 6.3V/7.0V, 264 lumen/38 lumen, 2.63A/0.75A.

What is the rated wattage of the "old 6 volt automotive headlamp"?

Generally speaking, each of the two incandescent lamps connected in series acts as a variable resistor with their resistances determined by their filament temperatures. Disabuse yourself of the notion that 6 volt rated lamps will drop 6V across each of them when connected in series across a 12V supply. If they have the same part number and contain nearly identical filaments then their voltages will be nearly identical, but lamp voltage drops won't be when two radically different filaments are connected in series.

Can you measure the current draw and voltage drops?