I am running down a difficult fuel pump problem with my 73, 2.0 with FI. The circuit board on Brad Ander's site shows the position of the 86 and 85 pin swapped. The first image is from Ander's site. The second one is from one of our members - Tom who put in in my previous thread. Tom's pic is the same as the one that Dr. 914 has in his 700 Tech Tips book. Which one is right? Is this image as if i were viewing from the bottom so I can see the traces on the relay board? It is important for me to know since I need to know which one should have power when following Brad Ander's troubleshooting.

If i follow the print on the relay itself, it looks to me like the Ander's one is mislabled. The relay itself shows the 86 pin on the driver's side of the power relay pins and 85 being on the passenger side.

I need to know if socket 86 on relay 75 has 12V when the key is on relay boards that are good. Mine does not have 12V to 86 (socket on driver's side). If other's do have power there, it looks like I may have a bad board.

Can someone check theirs and let me know?

Click to view attachment




Tom and Dr. 914's drawing


Click to view attachment

Warren,
It doesn't matter what number is assigned to the position. One side is power and the other is a switched ground. The fuel pump relay socket should have power to the socket at the 3 O'clock position ( pass side), no matter if it is labeled 85 or 86.
Follow it down from #87 of the power relay. When the power relay is energized, then the fuel pump relay should have power to the socket at the 3 O'clock position. When the ECU provides a ground to the 9 O'clock position ( driver's side), then the fuel pump relay is energized.
If you look at the relay and the sockets, the numbers are reversed between pics for relay #75 but are electrically the same.
Tom

I hate electrical problems!

When I look at the diagram, what i see usually labeled as 86 and is at 7 oclock postion does not have power to the pin on the fuel pump relay - it doesn't have power during the first 1 1/2 seconds after i turn the key. I think it is supposed to have 12V when I first turn the key - unless i am chasing my tail here.

Warren,
Looking at the lower of the two pics, 87 should be +12 volts when the fuel pump relay energizes, so you are thinking correctly. There are reasons why this may not be seen. One is if there is a low ohmage short on one of the traces that 87 feeds. It feeds the fuel pump relay and the AAR. Since you already confirmed that the fuel pump works by jumpering pin #13 to known power and the fuel pump works, my next idea would be to eliminate the AAR load by disconnectiong the AAR. It is possible for that wire to get a low ohmic valus short and cause a heavy load which could cause you to see no +12 volts at pin 87.
The other thing I would check is the two smaller of the 4 red wires at the battery positive to make sure they are clean and tight and don't have frayed strands at the solder connection.
Tom

The factory manual shows boards for 71,72, and 73.

the 72 and 73 are the same.

The 71 is opposite. That shows 85 on the left and 86 on the right.

John