Question for Dimmer Switch replacement on '67 Beetle

[JRinCali]

I'm replacing the dimmer switch and I see the new switch has one more wire jumper than the original switch does. The JBUGS order page says the following:

"The relay MUST HAVE POWER to the #30 terminal to operate. If your wiring does not have a power wire to the #30 terminal a "jumper" wire can be run from the #56 terminal to the #30 terminal."

Ok.. seems pretty straight forward.

My question: what gauge wire do I use if I run a wire from #30 to #56? My apologies - i'm a novice so unsure of what to ask for at the auto parts store. Thank you!

JBUGS:
https://www.jbugs.com/product/111941583.html?utm_s...oduct-link

[runamoc]

a small gauge wire will work as it is only needed to power the internal relay coil, 18 gauge
_________________
Daily driver: '69 Baja owned 44 yrs - Plan B: '81 Rabbit Diesel LS Deluxe - Plan C: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs-
VW Wiring = It's just wires

[JRinCali]

[ashman40]

I just want to confirm your are referring to the headlight dimmer RELAY and not the dimmer switch in the turn signal lever? The 5-prong dimmer relay has a #30 terminal, the dimmer switch does not.


I'm not certain there is a single answer to this question? Here is the non-US '67 wiring diagram:

The J2 dimmer relay just to the left of the fuse box is a 5-prong relay. Note that the red wire has a "2.5" in the wire path. This is the metric wire gauge and is the same size as the white/black #56 wire coming from the headlight switch. It is not clear which is the source of power for the headlights?

Here is a pic of the circuit diagram from the side of the aftermarket 5-prong dimmer relay case:

This diagram suggest that the headlights (hi or low) are powered from the #56 wire via the latching arm with the small "cross" in it (indicating this is a latching relay).
You can also see the #30 wire wraps over the top and while the relay is energize it is connected to the 56a (high beam) terminal for as long as the dimmer switch is closed. This means if you apply the dimmer switch while the headlight switch is OFF, current coming thru the #30 wire is momentarily powering the high beams. The #30 wire needs to be thick enough to carry the current draw from the high beams. This explains why the wiring diagram has the same size 2.5 wire (12AWG) running to the #30 terminal.

Even if the #30 wire does not power the headlights themselves... if not certain, using thicker wire for the short run from the fuse box to the relay does not hurt.
_________________
AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[runamoc]

[67rustavenger]

I replaced the OG headlight dimmer relay recently with a more modern item.
https://www.thesamba.com/vw/forum/viewtopic.php?t=742361&highlight=headlight+relay
The relay works great.
_________________
I have learned over the years.
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There's never enough time to do it right the first time. But there's always enough time to do it thrice.
GFY's Xevin and VW_Jimbo!

[ashman40]

They are the same relay from different makers. The circuit is the same just turned on its side.

The 12v constant INPUT power enters at #30 and first connects to a resistor(?) bridging #30 and S. This is commonly used along side relays/coils to dampen any spikes as the relay is powered off.
The #30 circuit continues to the actual relay coil (larger box w/ slash thru it). This coil is energized when the S terminal is grounded by the dimmer switch and momentarily pulls in the bar (2 lines with triangle) for as long as the S terminal is grounded. This bar toggles the pole with the cross in it and momentarily closed the pole at the end of the #30 circuit.
#30 circuit continues on to the pole at the top or right side depending on which diagram you are looking at. This is not connected to anything while the relay is OFF, but while the relay is energize it connects #30 to the #56a terminal (high beam OUTPUT). This is what allows the 5-prong relay to "flash" high beams even while the headlight switch is OFF and not powering the 56 circuit. This "flash" is the extra functionality offered by using a 5-prong dimmer relay.

What can be a bit confusing in each diagram is where the 56 and 30 circuits cross, and the 30 and 56b circuits cross. The lines cross over each other but there is no "dot" indicating these circuits are connected. 56 and 30 are independent of each other and the 30 circuit only powers the 56a OUTPUT terminal and does not power the 56b terminal.
If the 56 circuit is powering the 56a terminal while the 30 circuit is closed with 56a the current flow over 30 may be less as 56 may carry some of the load. But if 56 is latched instead to 56b then 30 is powering the high beam filaments all by itself and carrying the full load of the 55W x2 headlights WHILE the dimmer switch is depressed. The #30 wire needs to be sized to support at least 110W while the dimmer switch is depressed.

This is how these aftermarket relays are apparently designed (based on the presented circuit diagrams on the relays themselves. A similar diagram exists in the non-US VW 1200 Beetle wiring diagram suggesting the OE 5-prong dimmer relay worked the same from VW.

See the dimmer relay "J" in the above diagram (current track 11). The circuit is the same but one thing to note... the red #30 wire connected to the dimmer relay is not a 2.5mm^2 wire, it is a 1.5mm^2 (14AWG)! So here the wire gauge is smaller for the red #30 wire running to the dimmer relay.


This is why I said there may not be one answer. We have conflicting wire sizes that perform the same function across different model year wiring diagrams. Going with the thicker wire is the safer approach when uncertain.
_________________
AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[runamoc]

using the jumper between #30 and #56 means there is no flashing the hi-beams feature because #30 is not hot until the headlight switch is pulled out supplying power to #56 and the jumper can be a small gauge wire connected to #30 because it is just needed to pull in the relay. NOW if he wants to have the feature of flashing the hi-beams, that your post is about, yes the wire going to #30 would have to be a larger gauge to handle the current of the hi-beams AND without #56 being hot from the light switch. #30 shouldn't be connected to wire #56 with a jumper as it would 'back feed' power to the light switch in your configuration. Remember, it's just wires
_________________
Daily driver: '69 Baja owned 44 yrs - Plan B: '81 Rabbit Diesel LS Deluxe - Plan C: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs-
VW Wiring = It's just wires

[ashman40]

Doh! My bad. I just re-read the initial post and the question was what gauge wire to use for the "jumper wire" between 56 and 30.
I think I stopped reading at "dimmer" and "The relay MUST HAVE POWER to the #30 terminal to operate", then went on with how to wire #30.

The length of a jumper wire between 56 and 30 is so short any decent gauge wire will work. 18AWG would probably be the smallest gauge I would use.

As a test. Once you have the jumper in place, turn on the headlights and have someone pull on the dimmer switch and hold it for a reasonable amount of time. Do this a few times. Feel the jumper wire. If it is hot to the touch this is a sign the wire gauge is too small for the current load. Hot wires could also mean bad quality connections so always good to check new wiring to make sure they remain cool.
_________________
AshMan40
---------------------------
'67 Beetle #1 {project car that never made it to the road }
'75 Beetle 1200LS (RHD Japan model) {junked due to frame rot}
'67 Beetle #2 {2019 project car - Wish me luck!}

[KTPhil]

[runamoc]

[JRinCali]

[quote="runamoc"][quote="KTPhil"]

[runamoc]

[ashman40]

[JRinCali]

Yes, Dimmer Relay. Thanks so much for your guidance -- very helpful.

[KTPhil]

Some info on relay wiring and adding the "flash to pass" feature:
https://www.thesamba.com/vw/forum/viewtopic.php?p=9495460

If you don't want this feature, the thinner jumper will work. But if you intend to add the flash function, then the wire from terminal 30 to "always-on power source" MUST be heavy enough for with lamps simultaneously (2.5mm, or 10ga).