Hi Phil,

>the connection terminals on the relay can be another indicator. They can get >relaxed somewhat from the heating and cooling.

I think the relay terminals get beat up when the relays are removed from
the socket. Rocking back and forth to get a relay removed instead of pulling the
fuse block in a 700/900 and prying it up with a tool leads to spreading open
the socket pins. It only gets worse with repeated removal and insertions.

You can make a gauge for the common 0.250" female spade connector used in
relay sockets using a male spade connector crimped and soldered to a piece of
stiff copper wire. If the pins are loose you need to remove the pin and carefully form it back so it's tight. (I use vise grips that to avoid over-doing it)

To remove pins from fuse block sockets you can make a nice removal tool from a
bicycle spoke and just grind a this straight slot screwdriver tapering gently
about 1/2" from the end and slide it down the back of the connector to release the locking barb.

Ron Kwas has a very nice website focused on older Volvos.
http://www.sw-em.com/techarticles.htm
Check out these web pages that are relevant to every Volvo:

http://www.sw-em.com/Wiring%20Notes.htm#the_lowly_250_push_on_terminal

http://www.sw-em.com/Deoxit_D5_Additional.htm#my_recommendations

http://www.sw-em.com/voltage_drop_in_headlights_power_in_hex_connector.htm

There's a lot of good stuff to know at his site.

For Derek, Your comments about the fuses is spot on, and see the above links
where he suggests ACZP paste on the fuse sockets and fuses after they're cleaned.
There's corrosion from exposure to the elements and also possible electrolysis
going on with possible dis-similar metals that make the zinc paste a good option.

I wonder how copper based anti seize being a straight up conductor
might stack up with ACZP on 240 style fuse sockets?

I haven't seen troubles like the 240 style fuses with the later style ATC
fuses that started with the 700 series but maybe ACZP paste would be desirable there too? I have noted that the cheap ATC fuses from you know where are un-plated steel, and not like the quality zinc plated OEM variety.
(Don't use the junky ones)

Bill

This problem can also cause the fuel pump fuse to overheat. If it is one of the later plastic bodied fuses, they can soften or even melt. When they soften the contact pressure at the ends reduces and makes them overheat even more. Go out of your way to get an original type ceramic fuse for at least this position in the fuse box. Plastic ones don't look much different but if you give both types a scrape with a sharp knife you'll be able to tell which is which. Beware, plastic ones are often labelled as ceramic. It is possible to swap the fuse link from a plastic to a ceramic body if you are careful.