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On 13 Mar 2005 at 23:19, Dave Pallo wrote: > >>>That is the other end of that wire on #85. Try grounding that wire, in > the engine compartment, with the key on. This should make the pump run.<<< > > I can supply a ground to that connection, Russ, and the pump will > run.....but isn't that just bypassing the function of the brain which is > determining when the pump runs and when it doesn't run?....... Correct, but this is a good way to test the relay and all the wiring from this point forward. > I don't know when a condition would be that the brain doesn't want the pump > to run, do you?... The brain should provide a ground for ~1 second immediately after you turn the ignition key ON, regardless of whatever else happens. If you see this, you know that the brain is working. After that, it only provides that ground if it has seen the trigger points moving within the last second. > Is it a safety thing?... Yes, since the brain is keeping watch on the running of the engine, it knows when the engine stops. If you were in an accident that broke the fuel line, the engine would stop and the brain would then cut off the pump, reducing the likelyhood of a fire. It's a very important safety feature which we have discussed here often. If your brains don't seem to be controlling the pump, you should inspect the wiring between that junction in the engine compartment and the brain connector. It's EXTREMELY unlikely that you have found 3 brains in a row that were all bad in this function. You should also check the power wires to the brain, since the pump control function won't work unless the brain is getting power. There are TWO power wires to the brain, and they both have to be connected for everything to work. Check them at the relay under the back seat and also in the engine compartment, hidden somewhat in that wiring snarl in front of the pressure sensor. What year is your car again? If it is a '70 or later you can check power by just verifying that you can hear a series of clicks from the injectors as you press the pedal down with the ignition ON. -- Jim Adney jadney@vwtype3.org Madison, WI 53711-3054 USA ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~