Volvo Relays

Mine is a 1991 Station Wagon, 740. 140K miles. I had a no-start several
days ago but it has started OK since. I suspected the fuel pump relay so I
pulled it and put it back in (presumably cleaning the contacts in the
process). The car has been fine since then. But I am worried about certain
relays. In the front row, the K relay (central locking?) is too hot to
touch; the J relay (window?) is quite hot (but not as hot as K), and the
fuel pump relay is quite warm. In Brickboard I have seen two views; "Volvo
relays are always hot", the other "A hot relay is a bad relay".

Does anyone have any views on this (the others are are only very slightly
warm or only ambient temperature)?

Thanks,

John

 

Dunno what is normal but I don't like hot electricals. I saw a suggestion to
drill some small holes in the casing... while it's off. I followed the
suggestion with a new fuel pump relay 8 months ago but who knows if it will
help? They did say 7 years was about normal lifespan for those (1980 265),
which doesn't sound very good - seems something shortens its life.

 

They're made by Bosch and have circuit boards inside. When they get old the
solder joints at the connector pins tend to crack and result in an
intermittant connection. If you know how to solder or know someone who does,
or feel like spending $15 on equipment and a few minutes practicing, it's
fairly easy to pop the cover off and resolder them.

 

If it's getting more than just a little warm, you've got a bad connection or
excessive load. I failing fuel pump will draw too much power and melt the
relay and connector. Also once the connector gets hot it oxidizes which
causes resistance and then more heat. I suggest checking the current draw of
the fuel pump, if it's pulling more than 10A it's probably worn out.

 

The car is a l991 and it did have fuel problems in 2000. The fuel pump was
then replaced and a new relay installed (date code 1999, made in Hungary).

I will replace the relays one at a time, starting at the hottest and see
what happens.

Thanks.

 

This is what it can look like: http://www.viatrack.ca/Misc/badcon2.jpg


Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

 

Here's a link on an article I wrote, aimed at beginners, on how to
solder:
http://w6rec.com/duane/bmw/solder/


__ __
Randy & \ \/ /alerie's
\__/olvos
'90 245 Estate - '93 965 Estate
"Shelby" & "Kate"

 

Thanks, everyone, for great comments and suggestions. I'll do the
resoldering first (I'm well experienced) and will go from there.

John

 

what a brillant shot thank you

 

It was taken with a digital camera held manually against the eyepiece of a
microscope. Microscope projects image at infinity so there is no trouble
with focusing. Anyone can do it.


Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca