[T3] Fuel Pump Relay - 69 Fastback

Jim Adney jadney at vwtype3.org
Sun Jul 11 22:55:43 PDT 2021

On 11 Jul 2021 at 21:48, Tim Schiller wrote:

> My 85 & 86 wires no longer have the white plastic cover on the pump relay.
> Is it possible to replace? 

Possibly. I'll have to see if I have one I can get to. Do your female faston 
lugs still have the locking tab on them?

> I did not cut any wires but did ground the 85 pin. When I turn key on, pump
> runs. Turn key off pump stops. So I think this tells me pump is good and it
> is not my ignition. 

Okay, this tells you that the brain is not grounding that wire, so the relay was 
not being activated. Does the engine start now?

> This appears to indicate there is an issue with the wire labeled in Bentley
> as T1 , 19 which I believe means it goes to the ECU #19 terminal. Not sure
> what is meant by T1, if anything 

T1 is a single wire inline connector. It connects that wire from the relay to the 
FI wiring harness wire #19. It's a brown, translucent plastic connector 
bundled with the wiring harness in front of the engine, just to the left of the 
IAD (Intake Air Distributor.) Check there to make sure the wires are good 
and properly connected inside.  

Reconnect the wire to the relay, turn the key ON, and then use a separate 
wire to ground the connectors inside T1. You don't have to disconnect 
anything inside T1 to do this. When you ground T1 you should hear the relay 
click and the pump run. If this happens correctly, you have verified 
everything from T1 forward.

If everything from T1 forward is good, that leaves only the wire from T1 to 
the brain, the connector to the brain, and the brain itself. Unless you find an 
obvious problem in T1 or in the wires, the fault is probably that NPN 
transistor in the brain.

I can replace the transistor, but it's probably not worthwhile doing, as I can 
sell you a replacement B brain for less than the parts & labor to do a 
replacement. You have an early '69, which may have come with an A brain 
(A suffix at the end of the VW part number.) If, by some chance, this car still 
has an A brain, you definitely want to replace it with a B, which superceeded 
the A. I believe most '69s came with B brains. I have known good, used, 
tested B brains for $50 plus shipping. If I ship you a brain along with the 
other parts you've asked for, the extra shipping cost would be minimal.

Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA

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