Voltage spikes and relays

Henry A Harper III hah at alumni.rice.edu
Wed Feb 27 17:10:40 PST 2008

There are at least 25 "relays" or things that look like relays scattered
around the car. Some could be cheaper than $60, some could be No Longer
Available. You (or your shop) need to have a Bentley manual for the car if
you expect to do any serious troubleshooting, there is no substitute.
"Motorboating" could just be the Bose system warning you that it's about to
start a fire and needs to be yanked. What does the dash gauge or climate
control diagnostic display say about these spikes?

> My '91 200 TQ has developed intermittent electrical spikes, which
> causes problems with the audio system.  The radio and speakers were
> checked out, and they are not causing the problem.  The audio tech
> believes the problem may be a result of a faulty relay.  Where can I
> find a schematic diagram showing the relays?  How many relays are
> there on this model?  Also, what do the relays cost?  I've heard that
> they may be about $60 each.  I suspect they're more.  I don't know
> much about the car's electrical system; fortunately I've got Becker
> Audio in Hatboro, (north of Philadelphia) doing the work.  Becker's
> rates are fair and the shop has an excellent reputation.     Thanks
> for the help.

More information about the 200q20v mailing list