Melted headlight relays.. protect them!

[slowcoach]

I lost my dipped beams the other night, so had to scoot home with the side lights - luckily not far from home this time.
Today i went in to investigate, after confirming the oroginal vw wiring was in tact and working correctly still. I use the boomslang headlight loom, and have had it fitted for a few years now.



anyway, i saw the relay connectors had all melted :/ not being able to pull the relays out at first, i went looking for the earths which looked okay (checking for high resistance problems). but when i prised off the relays from the connectors, saw this...





crumbling terminals and lots of rust. one of the terminals had completely disintegrated when when i removed it.

so protect them relays i guess! ill replace them and put them into some tuppaware or something? they had just been tucked behind the grill for a few years. yet another fix i didnt want to pay out for! hmmm wonder if i can just replace the relay holder..

[Mocki]

Cut the holders off and replace with normal spade connectors of the correct size , and grease them up after
Buy the relays that have a bolt hole fixing built in .

[Oldiebut goodie]

Use pukka waterproof relays and bases rather than ones for interior use.

[slowcoach]

Good idea :-)thanks mocki. The two relays are different, one does high beam and one does dipped, one has 4 pins one has (used to have) 5. Is that how they're identified to get new ones?

[CJH]

Good idea :-)thanks mocki. The two relays are different, one does high beam and one does dipped, one has 4 pins one has (used to have) 5. Is that how they're identified to get new ones?

You need to make sure that the replacement relays match the circuit diagrams printed on the housings. Your 4-pin 'HID' relay is a 'make or break' relay that either connects or disconnects pin 30 to pin 87 according to whether power is provided across pins 85 and 86. Your 'CAR' relay is a 'changeover' relay that connects pin 30 to either 87 or 87a depending on the power across 85 and 86. Not all 4 and 5-blade relays will do the same job - see the 5-blade R30BT here for instance, which turns on two 87s instead of switching between 87a and 87 (the R20BC on that page seems to be the right sort, but is 30A, rather than the 40A of your original).

I'd say your holder melted because pin 30 on the CAR relay corroded away, leaving only a tiny current path, which would have heated up under high current.

I put my relays in a plastic watertight junction box behind the headlights.

You can buy replacement relay sockets. This one comes with latching terminals that click into place in the socket.

[CJH]

There's a good reference for relay types here. It points out that there are two different types of pin configuration for the 5-blade changeover relays. It looks like your original one is a 'Type B', but of course if you're rewiring it you could configure it for either.

[CovKid]

I'd never put a relay anywhere other than inside a vehicle. Doesn't matter what you do, eventually moisture gets into them and they fail. My headlight relays are just behind my fusebox - and taped up.

[slowcoach]

Thanks cjh, a big help - I've read up and got new ones ordered. I'll grease and seal up the new ones. Cheers!

[California Dreamin]

Simple waterproof junction box does it for me and quality relays.

https://www.screwfix.com/p/schneider-el ... 45mm/63295" onclick="window.open(this.href);return false;

Martin

[Sir Brixalot]

Timely thread. Just bought something similar on facebook and was wondering about water getting in the relays. Wondering if a plastic bag with a cable tie would do the job

[California Dreamin]

I've seen plastic bags used but the wire entry won't be water tight so must be placed at 6 'O'clock to drain. A plastic box is better as it has multiple rubber grommet wire entry points that (if cut correctly) seal around entry wiring. Easier to physically mount and looks better. VW already use a similar plastic box in the engine bay to protect wiring joints etc.

Martin

[slowcoach]

Finally got round to fixing this today, as recommended above somewhere, i snipped off all the wire ends and got new relay holders. I got some proper uninsulated crimpers which actually worked. Also grease d anything exposed and bagged up the relays and orientated upright, which are now behind some new fibre boards deflectors I made from a for sale sign. Should be alright, touch wood as always

[crazyhorse]

just fitted these, so good to know