That MIGHT work if the wattage of the bulbs is high enough..... I'm assuming that the back light(s) will come on, just not flash ...(If the lamps don't come "on" at all, you have other problems....)....Correct?......
This is why......
A flasher is essentially a self operating switch... The movable contact is a bi-metallic strip that "bends" as it gets hot (one side/type of metal expands faster than the other, causing it to "curve away")... When that happens, the contact points open shutting the lights off.... as the bi-metallic strip cools, it returms to its original position, closes the contacts, and lights the lamps again.... then the whole thing repeats causing "flashing".
The more lamps (the greater the draw) the faster the strip "heats-up"and the faster it flashes..... BUT, it requires a certain "minimum draw" to heat it enough to operate.... this is the wattage printed on the module..... Without MORE resistance in the circuits, the strip never "gets" to the point where it "heats" enough to open., or it takes a long time to open causing slow-flashes.......
I hope this explains the process better for you..... Steve