first of all pls clarify S25/5 and B11/7.
In my diagram, it shows that S25/5 is applicable to MY1986 and MY 1987 only. The component location photos seems to indicate that this S25/5 is in the same location as B10/8. Also, I cannot locate B11/7.
This is what I did with engine basically cold:
1. I isolated K9 as the relay that turns on the aux fans. This is relay code C in the fuse/relay box.
2. Pin 85 of k9 is grounded with the ignition on.
3. Pin 85 of k9 is still grounded with B10/8 wires disconnected and ignition on.
4. B10/8 ( color blue installed on top of t/stat) tested with high resistance.
5. K9 is the only black relay, so i could not test symptom with any other relay.
K9 contacts pin 30 and pin 87 tested NO (Normally Open)
would appreciate further assistance...