[urq] buzzing relays

[DGraber460 at aol.com]

I have just started to notice 2 relays under the dash on my 83 WX URQ that 
intermittently buzz. It is more a cross between a buzz and a clatter. My car is 
a late 83 and has the fuse box under the hood. There are still 5 relays above 
the drivers left knee. The 2 noisemakers are orange and both are #431 951 253 
H. They show a diagram of control voltage of track 85 & 86, and switched line 
of 30 to 87.
The family album lists that number relay as 
    fog lamp
    fuel pump relay 
    electric fan
    hot air fan
    high pressure switch
Any ideas what these control, and why they would start to occasionally buzz? 
Everything seems to work fine including the horn.

Dennis
Denver
"Good judgment is a result of experience, which is often the result of poor 
judgment"