My 1993 Plymouth Acclaim is vibrating real bad after I reach a speed of 35mph. What could be causing this?

neither
most probably needs a wheel alignment as what you describe is castor wobble
have a suspension professional check out the front end for loose worn parts and wheel bearings and get an alignment done

check the fan relay

Try a new fuel filter. If that doesn't work, have your fuel pump tested for proper pressure. Bad gas, injector partially clogged, bad fuel pressure regulator, bad idle valve, etc., etc. List is endless-gotta start somewhere>fuel filter and fuel pressure check. Also, have your engine computer checked for trouble codes-you need an OBD 1 scan. Walmart sells a code reader for around 25-30 dollars. Make sure it is the right one for your car. If any trouble codes come up, it should direct you to the problem. Good luck.

bad earth on a back light i suspect providing their europeon standard lights with yellow seperate indicators and not them funny american ones with a stop and tail and indicators all on the one bulb

if it sits there and seems to rev up and down, it is probably your throttle position sensor. Mine acted up very bad, expecially when leaving the highway back into city driving when at a stop sign.

My sincere apologies for the delayed response.
I am personally going back to answer your unanswered questions.

I do not know if you still need this information, but I am going ahead and answering it anyway. You may want to Print the Diagrams for future use.

CLICK on the following LINK. It has the Belt Diagrams you will need.
If you would: Before Clicking: Let me know if this helped you, or if you have any additional information questions. Feel Free to contact me at FixYa.com!
Again my apologies...
Thanks!
http://www.2carpros.com/car_repair_information/year/1993/make/plymouth/model/acclaim/1993_plymouth_acclaim_drive_belt_routing_diagram.htm

most cars use dome or cig. fuse with radio fuse.check all fuse conditions .may have more than one bad fuse

If all is well, and within reasonable shape & mileage, 25-30 shouldn't be out of reach on highway at normal speeds.

check to make sure hose clamps are tightened enough

cut old clamps and hoses and replace with new fuel line hose