[T3] Fuel Pump Relay - 69 Fastback

Fri Jul 9 21:07:22 PDT 2021

It’s hard not to run out right now and check all those, but will early tomorrow morning. Thx for some direction 

Sent from my iPhone

> On Jul 9, 2021, at 8:58 PM, William Jahn <willjahn975 at gmail.com> wrote:
> 
> Last thought , if you find there is an issue with the power relay I think
> Jim may have some good used ones or just a 30 amp Bosch relay wired the
> same way will work , they all work the same way. It's just the amperage
> that differs.
> 
>> On Fri, Jul 9, 2021 at 8:52 PM William Jahn <willjahn975 at gmail.com> wrote:
>> 
>> From what you said I doubt if the pump relay is the issue. I bet you find
>> that red /black wire at the battery is either loose or corroded or the
>> eyelet on the end of that wire is not making good contact to that wire. If
>> it's not there check the spade connector on the power relay. It has to be a
>> good connection at both ends. If it is that red/black I would still make
>> sure the power relay spade connectors are all sound and fit snug . I went
>> through mine a while back and found the brown ground screw was fine yet the
>> spade connector only had one rolled edge . It worked I was just checking
>> and happened to find it. So I checked them all . it's even possible the
>> power relay contacts have high resistance yet they don't have that much
>> current to burn them. Mine is the original on my 73 I decided to just check
>> for voltage drop and found there was some so I removed the relay cover and
>> cleaned the contacts. This is my only car and the last thing I want is to
>> be sitting somewhere stranded.
>> 
>>> On Fri, Jul 9, 2021 at 8:34 PM William Jahn <willjahn975 at gmail.com> wrote:
>>> 
>>> On the positive battery post there is one red/black wire that runs across
>>> from the battery pos to 30/51 on the power relay . That wire is fastened to
>>> the pos battery clamp  bolt by an eyelet then the battery clamp nut . This
>>> wire is the only power to the power relay . Check that to make certain it
>>> has a good connection to the battery . If there is a voltage loss there you
>>> will not get 12 volts at the pump relay . All it takes is it being loose or
>>> corroded . It runs all the way from the battery to the power relay. That
>>> may explain why it works then doesn't. That is the contact part of the
>>> relay that sends power to 85 on the pump relay. If it's loose or corroded
>>> all it takes is to try to start the car and you get an arc which might be
>>> just enough for it to make enough contact to run the pump . I would check
>>> that before going any further. If there is going to be a bad connection
>>> either it's loose and you know how battery cables get corroded . It's
>>> simple to check and rule it out . It runs near the top inside of the wall
>>> held by small tabs . You will be able to see it easy.
>>> 
>>> On Fri, Jul 9, 2021 at 8:01 PM Tim Schiller <schillertim at comcast.net>
>>> wrote:
>>> 
>>>> Replaced fuse with 8 amp just in case it was bad. Bentley manual shows
>>>> most fuses are 8 amp except 9 & 11 are 16 amp. Appears several mine are 16
>>>> when they should be 8. Separate issue.
>>>> 
>>>> I hear the 2 clicks, both the fuel pump relay a main power relay when
>>>> key is turned on.
>>>> 
>>>> I tested pump again with a direct power source and it buzzes. Car
>>>> actually started a ran for a while after immediately hooking relay back up.
>>>> However, when I turned it off it would not start again. When car was
>>>> started, the 87 pin was reading 12V
>>>> 
>>>> Back to testing the fuel pump relay. The voltage to pin 87 is not
>>>> consistent. Turning key I sometimes get a zero reading, sometimes a 5-6V
>>>> reading and sometimes a 2-3 V reading. I tested when the pump wire was not
>>>> attached trying to eliminate the ground wire to the pump as a possible
>>>> issue. Not really sure how anyone can follow that brown wire between relay
>>>> and pump.
>>>> 
>>>> I found some help to turn key so I could hold on to pump. There is a
>>>> little bit of a buzz when the key is turned on, but didn’t seem that
>>>> strong. It feels like it is priming or buzzing for 1-2 seconds when the key
>>>> is then turned off. Seems just opposite of what it should be doing
>>>> 
>>>> Currently trying to find something on Samba forum for a similar problem.
>>>> I really struggle with the search function on Samba
>>>> 
>>>> 
>>>> Sent from my iPhone
>>>> 
>>>>> On Jul 9, 2021, at 12:39 PM, Jim Adney <jadney at vwtype3.org> wrote:
>>>>> 
>>>>> On 9 Jul 2021 at 10:48, Tim Schiller wrote:
>>>>> 
>>>>>> I will follow the ground and check the fuse
>>>>>> 
>>>>>> I did hook a reliable 12V to the red wire going to pump. Pump buzzes
>>>> loud
>>>>>> and clear.
>>>>>> 
>>>>>> I had purchased 2 relays and swapped just in case one was bad, but
>>>> same
>>>>>> results
>>>>> 
>>>>> One other quick check you can easily do if the car is in a quiet
>>>> place, is to
>>>>> listen when you turn the key ON. You should hear a relay click when
>>>> the key
>>>>> goes ON and a second relay click about 1 second later.
>>>>> 
>>>>> If you have questions about whether this is happening correctly, look
>>>> under
>>>>> the back seat, on the  driver's side. Mounted on the top rail, there
>>>> will be 2
>>>>> relays, each mounted with a single screw. One of them has a ground
>>>> wire
>>>>> under that screw head. Make SURE that screw is tight. That's the
>>>> ground for
>>>>> the main power relay coil.
>>>>> 
>>>>> --
>>>>> *******************************
>>>>> Jim Adney, jadney at vwtype3.org
>>>>> Madison, Wisconsin, USA
>>>>> *******************************
>>>>> 
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>>>> 
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>>> 
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