What do 'ff's' on my fuel display means on my 1990 mercury cougar

SOURCE: fuel pump relay location on a 1990 mercury grand marquis.

check the fuse .if the fuel pump was bad you blew the fuse . there is a inertia switch in the trunk or under the dash you could check . push the red button to reset relay should be under the hood in the fuse box check your book if you have one.

SOURCE: 2000 mercury cougar wont start

what is anti-theft light doing? It should come on solid for about 2 sec after you turn the key on then turn off. If it is flashing after this then it is not seeing the computer chip in the key and you have a PATS problem.

SOURCE: Turn signal stopped working 1990 Mercury Cougar

I had the same problem and the flasher is not located in the fuse box because it is not a normal flasher. the cougar has an electronic flasher unit that is located on the left side of the center console. the best and cheapest place to order a new one is amazon.com. they run about $30-$40

SOURCE: 1999 mercury cougar. won't start...cranks...battery ok.

V6 ? 4CYL? Have you verified SPARK? Did anyone check the "fuel pump inertia switch?" Its in the right front kick panel. If it was a "Anti-theft Issue" the light would be on or flashing.

SOURCE: 96 mercury cougar xr7 fuel pump

Check your local library for repair manuals...