Auto Trans. "limp mode" and relays

[superba]

Hi Doug,

Mechanical relays usually fail due to dirty, corroded, and burned contacts.
Audi packages (maybe used to) many in small cases containing circuit boards
and components.  They suffer from cold solder joints and excessive current
draw over time causing a solder joint to fail.  I've repaired several when I
had no other way to start my car.  You're right in trying to find out what
interacted to cause failure in the first place;  after all, a new relay
would also fail if the fault is somewhere else.  You'll have to look at a
wiring schematic and look upstream for likely to fail components.  Chances
are that the relay itself is the problem, however.

HTH.

Cheers!

Jim Jordan

         Message: 2
         Date: Sun, 7 Sep 2003 12:40:47 -0500 (CDT)
         Subject: Auto Trans. "limp mode" and relays
         From: "Doug Yoder" <yoderw at msoe.edu>
         To: <quattro at audifans.com>

        --------------------snip, snip---------------
         So, while I am tracking down a spare, I have some
         questions: what can
         cause a relay to go bad? do I run the risk of blowing the
         new relay when I
         put it in?  There don't seem to be any problems with the
         power getting to
         the relay (ie, it's not 20 volts or anything like that).

         Thanks,
         -Doug
------------------------snip, snip----------------------------