1979-1993 & 94 Conv [Subscribe to Daily Digest] |
I recently received some interesting and valuable information from Tom Townsed with regard to the time-delay relay on the 1991 900S. Tom was good enough (and patient) to answer my questions. Here is what I learned:
- In the old relay there are 5 pins, the new one has 4. Pin layout configuration is also different.
- Pins 15 and 31 in the old relay are not used for the new relay. Its part of the timer function on the old relay. The new relay fits right in because there is a matching receptacle in the relay panel.
-The Germans use numbers on wiring schematics and electrical terminals to
indicate circuits. A example is:
30 is battery power "usually constant regardless of ignition key position.
15 is power when the key is on.
31 is ground.
85 is the pin that feeds power to the coil that will turn the relay on.
86 is the pin that will complete the circuit through the relay coil and
turn the relay on if grounded.
87 is the load ...like fan or fog light and so on.
Function=
If battery power is at 30 and battery power is at 85 and you ground 86,
the relay will turn on and send 30 out to 87.
The reason for the relay is you can have large power wire at 30 that will
feed what ever 87 goes to.
There for you can use a very small switch to complete the circuit through
the relay and turn it on.
If you tried to run 30 through the small switch to turn on a powerful fan,
it would burn the switch up.
Get the idea?
The old relay is less reliable and expensive. Failure will keep the fan running with the engine off and drain the battery. The new relay is more reliable and only costs $5. So for some inexpensive peace of mind, I spent $5.
Mark
1991 900S Sedan
1997 900SE Turbo Convertible
posted by 192.249....
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
![]() |
![]() |
![]() |
![]() |
![]() |