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Who.Me? 
Samba Member
Joined: July 14, 2014
Posts: 2211
Location: UK (South)
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 Posted: Sat Dec 31, 2016 7:24 am Post subject: Hard start relay |
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With the transmission out and everything cleaned up, I've had a chance to look properly at a relay that was mounted on the firewall in front of the transmission.
From the wiring, I'm fairly sure it's a hard-start relay, but the connections don't make sense and I'm not sure if it should have worked at all.
The relay is a 6V bosch unit (0332003016) although the truck is running 12V electrics. The relay has terminals 85, 86, 87 and 30/51.
It was wired up like this...
85 - Ground to body
86 - Appears to go to the ignition (the wire disappears in to the loom)
87 - Battery live (circular connector connected to the round post on the starter motor to which the main battery tail is connected)
30/51 - Fly-lead connected to the soleniod. I dislodged this lead before I took pictures, but it has a spade connector at each end. I can tell from the spade connector that it was attached to 30/51 and, given its length, the spade connector on the soleniod is the only place the other end could have been connected to.
What has me confused is that, from comparing wiring diagrams online, e.g http://www.thesamba.com/vw/forum/viewtopic.php?t=534436, 87 and 30/51 appear to have been transposed?
I don't understand how this could have worked. Have I just misunderstood the wiring diagrams?
_________________
Andy
Looking for info on my truck's history. Are you from Campbell California or nearby. Do you recognise it? ... http://www.thesamba.com/vw/forum/viewtopic.php?t=636786
Last edited by Who.Me? on Mon Jan 02, 2017 1:48 pm; edited 1 time in total |
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Braukuche
Samba Member
Joined: September 03, 2004
Posts: 11005
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| Posted: Sat Dec 31, 2016 9:10 am Post subject: Re: Confused - Hard start relay connections |
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I wonder if that set up didn't just effectively bypass the hot start?
_________________
Go Reds! Smash state!
Retirement is here!
1956 Ghia
1959 SO-23 Westfalia
1960 double cab
1960 Baja Bug
1963 stretched double cab
1962 Golde sunroof Ghia
1963 356 B coupe
1963 Notchback
1967 21 window less rusty now |
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telford dorr
Samba Member
Joined: March 11, 2009
Posts: 3555
Location: San Diego (Encinitas)
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| Posted: Sat Dec 31, 2016 10:08 am Post subject: Re: Confused - Hard start relay connections |
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Technically, the relay will work either way - it's just a switch between 30 and 87. Conventionally, terminal 30 is always 'battery' and 87 is always 'load'. On the coil side, 85 is ground (or '-' connection) and 86 is +12 volts coil drive (or '+' connection - in this case, the start wire from the ignition switch). It's best to wire it this way, as some relays have a protective diode across the coil, and reversing 85 and 86 will cause the purple smoke to escape from the relay...
And you definitely want to run a 12 volt relay on a 12 volt system, for best reliability. Note: the relay needs to be rated for 40 amps, minimum. More is better.
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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Who.Me?
Samba Member
Joined: July 14, 2014
Posts: 2211
Location: UK (South)
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| Posted: Sat Dec 31, 2016 10:42 am Post subject: Re: Confused - Hard start relay connections |
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| telford dorr wrote: |
| Technically, the relay will work either way... |
Got it - 85 & 86 on the switching side can be transposed and 30 & 87 can be transposed on the 'load' side (assuming there is no diode in the relay).
I'd thought that the transposed connections on my relay had mixed the switching and 'load' circuits.
And I'll grab a new 12V relay before I refit the transmission.
Thanks for your help.
_________________
Andy
Looking for info on my truck's history. Are you from Campbell California or nearby. Do you recognise it? ... http://www.thesamba.com/vw/forum/viewtopic.php?t=636786
Last edited by Who.Me? on Sat Dec 31, 2016 10:44 am; edited 1 time in total |
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slow36hp
scott wimberley
Joined: August 09, 2004
Posts: 3113
Location: mukilteo washington
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| Posted: Sat Dec 31, 2016 10:42 am Post subject: Re: Confused - Hard start relay connections |
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| Who.Me? wrote: |
With the transmission out and everything cleaned up, I've had a chance to look properly at a relay that was mounted on the firewall in front of the transmission.
From the wiring, I'm fairly sure it's a hard-start relay, but the connections don't make sense and I'm not sure if it should have worked at all.
The relay is a 6V bosch unit (0332003016) although the truck is running 12V electrics. The relay has terminals 85, 86, 87 and 30/51.
It was wired up like this...
85 - Ground to body
86 - Appears to go to the ignition (the wire disappears in to the loom)
87 - Battery live (circular connector connected to the round post on the starter motor to which the main battery tail is connected)
30/51 - Fly-lead connected to the soleniod. I dislodged this lead before I took pictures, but it has a spade connector at each end. I can tell from the spade connector that it was attached to 30/51 and, given its length, the spade connector on the soleniod is the only place the other end could have been connected to.
What has me confused is that, from comparing wiring diagrams online, e.g http://www.thesamba.com/vw/forum/viewtopic.php?t=534436, 87 and 30/51 appear to have been transposed?
I don't understand how this could have worked. Have I just misunderstood the wiring diagrams? |
Funny I saw your pictures yesterday and almost commented that it was time to clean up the relay wiring. With such easy access I would move the into the engine bay to get them out of the elements.
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1958 custom camper
http://www.thesamba.com/vw/forum/viewtopic.php?t=483656
1957 oval
http://www.thesamba.com/vw/forum/viewtopic.php?t=426468&postdays=0&postorder=asc&start=0
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http://www.thesamba.com/vw/forum/viewtopic.php?t=186478&highlight= |
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Who.Me?
Samba Member
Joined: July 14, 2014
Posts: 2211
Location: UK (South)
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| Posted: Sat Dec 31, 2016 11:23 am Post subject: Re: Confused - Hard start relay connections |
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| slow36hp wrote: |
Funny I saw your pictures yesterday and almost commented that it was time to clean up the relay wiring. With such easy access I would move the into the engine bay to get them out of the elements. |
I've been considering it. Need to work out how to get the relevant wires in and out of the engine bay without drilling more holes though.
_________________
Andy
Looking for info on my truck's history. Are you from Campbell California or nearby. Do you recognise it? ... http://www.thesamba.com/vw/forum/viewtopic.php?t=636786 |
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Who.Me?
Samba Member
Joined: July 14, 2014
Posts: 2211
Location: UK (South)
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| Posted: Mon Jan 02, 2017 1:55 pm Post subject: Re: Confused - Hard start relay connections |
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| Who.Me? wrote: |
| slow36hp wrote: |
Funny I saw your pictures yesterday and almost commented that it was time to clean up the relay wiring. With such easy access I would move the into the engine bay to get them out of the elements. |
I've been considering it. Need to work out how to get the relevant wires in and out of the engine bay without drilling more holes though. |
Re the above; has anyone had any problem running hard start relay wiring parallel to the main battery cable through its engine bay hole?
Is there enough current in the battery cable to cause problems with inductance in the wires to the relay if they run that close and parallel?
_________________
Andy
Looking for info on my truck's history. Are you from Campbell California or nearby. Do you recognise it? ... http://www.thesamba.com/vw/forum/viewtopic.php?t=636786 |
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telford dorr
Samba Member
Joined: March 11, 2009
Posts: 3555
Location: San Diego (Encinitas)
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| Posted: Tue Jan 03, 2017 10:47 am Post subject: Re: Confused - Hard start relay connections |
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| Who.Me? wrote: |
Re the above; has anyone had any problem running hard start relay wiring parallel to the main battery cable through its engine bay hole?
Is there enough current in the battery cable to cause problems with inductance in the wires to the relay if they run that close and parallel? |
Shouldn't be a problem. Without a serious metal core of some kind, there's not enough coupling between the wires to be an issue.
_________________
'71 panel, now with FI
'Experience' is the ability to recognize a mistake when you're making it again - Franklin P. Jones
In theory, theory works in practice; in practice, it doesn't - William T. Harbaugh
When you're dead, you don't know you're dead. The pain is only felt by others.
Same thing happens when you're stupid. - Philippe Geluck
More VW electrical at http://telforddorr.com/ (available 9am to 9pm PST) |
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Who.Me?
Samba Member
Joined: July 14, 2014
Posts: 2211
Location: UK (South)
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| Posted: Tue Jan 03, 2017 12:18 pm Post subject: Re: Confused - Hard start relay connections |
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| telford dorr wrote: |
Shouldn't be a problem. Without a serious metal core of some kind, there's not enough coupling between the wires to be an issue. |
Good. Thanks. Have ordered a 12v kit. It's for big LED truck light-bars but has a 40A relay, fuse carrier and enough wire to allow me to mount the relay in the engine bay. Worked out cheaper than buying the parts and assembling it myself.
_________________
Andy
Looking for info on my truck's history. Are you from Campbell California or nearby. Do you recognise it? ... http://www.thesamba.com/vw/forum/viewtopic.php?t=636786 |
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glideking
Samba Member
Joined: February 02, 2013
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Location: California
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