The radio relay on a '91 is basically a standard Bosch relay. The only difference is that it has a 10A fuse sticking out the front that's internally wired to the relay output. So probably any fused Bosch relay will work if you swap in a 10A fuse (actually, any unfused Bosch relay should work too, but in that case you should probably wire in a 10A fuse somewhere).
Before you replace it, though, what makes you suspect the relay? Have you troubleshot with a multimeter first? Can you feel the relay click when you turn the key to on? When that happens do you get 12V to the radio or not?
Before you replace it, though, what makes you suspect the relay? Have you troubleshot with a multimeter first? Can you feel the relay click when you turn the key to on? When that happens do you get 12V to the radio or not?
