Lambda relay tricks

["Walter" <Whalt@xxxx>]

Someone asked me how to jumper out the Lamba relay for diagnostic purposes.
I am posting my directions here for the benefit of the group.

There are two ways to go about it. First determine which relay is the
Lambda relay. It's in the row towards the rear of the car and the second
from the drivers side. Pull the thing out and see what it looks like. The
socket has 5 connections. The connections on the car's right (#86) and left
(#85) should have 12 volts across them when the ignition is switched on.
This powers the electro-magnet in the relay and causes it to switch on.

The remaining 3 connections act like a double pole, single throw switch
(DPST) in an unlikely configuration. This is what makes it hard to figure
out how to jumper it.

The connection toward the front of the car (#30) is common to both 'throws'
of the switch. When the ignition is switched off, all the switch's poles
are isolated. When the ignition is switched on, the electro-magnet is
energized turning it into a magnet. This magnet attracts the metal arm
(#30) of the switch and pulls it into connection with the remaining switch
contacts (#87 & #87b), thus electrically 'shorting together' contacts #30,
#87, & #87b.

If you want to make this happen without the relay in place, stick jumper
wires in the relay socket shorting together these three connections. If you
decide to try this, be careful not to inadvertently disassemble the socket.
The female spade lug connectors in the socket are made to come out and are
supposed to come loose when you stick a wire down beside them. Sometimes
these fall or get pushed out of the socket by accident or when heat causes
the plastic to deform.

Another way to test this circuit is to remove the cover from the lambda
relay (provided it is one with a metal cover that can be removed without
damaging it.) Just straighten out the little crimps at it's base and pry it
off. Then plug the coverless relay back into it's socket. Using your
finger, press the little metal arm of the switch causing the contacts to
connect. With the ignition switched off, you should then hear the frequency
valve buzzing if everything else is right. Since the electro-magnet whet
bad in my relay, I used a tiny alligator clip to hold the contacts together
while I drive the car.

And if you try any of this stuff, do it at your own risk. These relays are
hard to pry out of the sockets anyway. The Lambda relay is even harder to
get out with it's cover off. Having these electrical connections exposed
increases your chances of shorting things out causing a fire or meltdown.

Hope this helps,
Walt Tampa, FL