Date: Wed, 6 Feb 2013 14:19:25 -0800
Reply-To: neil n <musomuso@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: neil n <musomuso@GMAIL.COM>
Subject: Re: No Start Cause: Relay Failure. PICS, Thoughts.
In-Reply-To: <5112c489.2864340a.3e7f.7358SMTPIN_ADDED_MISSING@mx.google.com>
Content-Type: text/plain; charset=ISO-8859-1
On Wed, Feb 6, 2013 at 1:00 PM, David Beierl <dbeierl@attglobal.net> wrote:
> At 03:12 PM 2/6/2013, neil n wrote:
> Well it certainly got hot enough to melt the solder around the terminal, but
> that was from high resistance and arcing once the joint had already gone
> bad.
Understood.
Since it's a yucky day outside, and I am suffering the remnants of an
Electrical Victory celebration, took some more pics of the relay.
Speaking of heat:
https://lh6.googleusercontent.com/-vCPFjWDwWyw/URLRuT7232I/AAAAAAAAGzc/W6AxiYxxQgw/s640/109%2520relay%2520suppression%2520component.jpg
70º C temp at coil windings. Interesting to me that's all. Relay is
powered from a "12 VDC" wall wart. Voltage may be higher.
>> The replacement 109 relay is a different design;
> VW relays with PCBs have a pair of molded-in rails inside the cover, that
> the board slides into to support it against overall distortion/vibration.
> Failing to mount the cover in this orientation will contribute to terminal
> failures.
Right. Yes. The old failing relay assembles as such. New one does not.
(No PCB on it). It's seeming more and more obvious to me that not
using a relay socket was a really bad idea.
>..... This particular relay is operated by switching the ground
> lead rather than the hot lead of the coil. All this suggests to me that
> it's being driven by an ECU output, is this correct?
Yes. Order of events AFAIK: key to ign. on 15 + --> ECU. Energized
ECU then sends - to power supply relay (109 relay). 109 relay sends
+ to main + buss in harness for fuel injectors, ECU, etc.
Slightly annotated diagram image:
https://lh3.googleusercontent.com/-8GS0_Zk_uJE/UQRc-4jPHLI/AAAAAAAAGtA/jibwhoITrAU/s800/power%2520supply%2520relay.jpg
>
>> .... Both the Jetta
>> Power Supply and Fuel Pump relays have a suppression component
>> (appears to be a resistor) in parallel on 85 and 86 so I would make
>> sure a substitute relay has same.
>
>
> Ok, how specifically does it appear to be a resistor? What does it look
> like, exactly? Any numbers, banded end, color bands, body material, body
> color, body shape? I guess a parallel resistor could be used to mitigate a
> voltage spike, I'm just not accustomed to the idea.
I may be wrong. Image of suppression component:
https://lh6.googleusercontent.com/-vCPFjWDwWyw/URLRuT7232I/AAAAAAAAGzc/W6AxiYxxQgw/s640/109%2520relay%2520suppression%2520component.jpg
At first glance looked like a resistor, but maybe not enough bands?
And for fun, a close up of the relay switch. Not that revealing, but
to my eye, part under magnifying lens, the contacts don't look too
bad.
https://lh4.googleusercontent.com/-vrLtjwmz4xI/URLRueP8Q9I/AAAAAAAAGzg/Jh2bqF0A6jE/s720/109%2520relay%2520contact%2520close%2520up.jpg
Not sure if VW wanted to save money on wire, and in the process make
sure owners would have to purchase a "special" relays, but the 109 is
obviously wired from 30 to one side of the coil, so only 3 external
connections required. The fuel pump relay is similar. Diagram image:
(ignore my annotations):
https://lh5.googleusercontent.com/-qjVqWgmKgiA/UQLzz0KnCHI/AAAAAAAAGq8/dV79PgDqWQg/s720/ABA%2520swap%2520coil%2520wire%253F.jpg
I wired in an external jumper lead from 30 to 86 of relay. It has worked fine.
Neil.
--
Neil n
65 kb image Myford Ready For Assembly http://tinyurl.com/64sx4rp
'88 Slate Blue Westy to be named.
'81 VanaJetta 2.0 "Jaco" http://tubaneil.googlepages.com/
Vanagon VAG Gas I4/VR Swap Google Group:
http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines
