Yo!

Running a relay for my Mk2 ignition (fuel pump runs off it also)

For some reason it randomly died yesterday, had been stood for a week whilst i was doing some work, nothing electrical but i was doing welding (yes, disconnected the battery) Wouldn't go when i attempted to start it, was the relay.

Swapped it for new one, started fine a couple of times... left it over night and its killed this one aswell

Any ideas? Have had a look at the wiring for the relay and all seems fine, cant see where it could be shorting out or anything.

Any help would be awesomeage as relays arent the cheapest thing to have break every time i wanna start my car

I told you what to check lol.

You got a meter with a multitude of functions?

zero testing equipment

Fuck

On the off chance you haven't got it sorted by then I got a multimeter in my boot that never gets used, you can use it at the poloshow if you need to

Is the relay switched by a switch, or just your key?

key

Hmmmmmmmmz

Got a 9v battery and your old relay?

You need a multimeter really man.

As Matt said we can have a look at the show but it's a pain then going, if it was fine for months then you did 2 within a day or whatever perhaps it's something else than a relay rated too less.

If your feed to the switching side is very very weak, or perhaps a bad contact somewhere, it may be that it switches and either doesn't have enough current to keep it engaged (so relay on) or that it's kind of bouncing off te contacts so constantly turning on and off and burning them out.

What angle does it mount on?

You can stick a 9v batt across the switching pins on the relay to see if it clicks and holds there, at least then you know the coil works okay to turn it on and off. But ideally you could check resistance over the load side when it's engaged also, and check out your feed/ground in the cars wiring too

what size relay are you using? and how much current does whatevers connnected to it draw? sounds like your burning it out tbh which is a sign that whatevers connected to it is starting to fail and draw more current than it does normally

Edited 2 July, 201313 yr by KiZ

Id imagine 30 or 40a, standard 4 pin relay Kiz,

Facet pump and ignition, so coil I guess? Think facets draw ~10a, not sure about coil, spikes i guess

if it draws to much you can end up burning the contact either on or off, and the hotter it gets the greater the chance of oxidising the wires making them go black and more resistant. relay is easy to test using 2 wires and the battery

relays are effort

Think I've sorted it now, touch wood.

Swapped for a 40amp relay, also put a fuse before it (as didnt before )

Tidied all the wires in scuttle, taped absolutely everything up that looked like it may end up/have been dodgy. Although i had a good look and all wires seemed sound.

I do think a main contributor may have been that one of the big connector block things in fuse box (one for lights etc) was loose somehow Fuck knows how but that's now sorted and I've got my reverse light back haha (hasnt worked for months)

Will see how everything goes. it seemed to go overnight before.. so wont know really until tomorrow.

One thing I've done is used spade connectors instead of soldering straight to the relay.. been a right pain haha! Have a spare relay on standby now

soldering straight to the relay is a pretty silly thing to do as the unit is encased in plastic which melts- so its more likely than not that the parts inside have drifted causing premature failure- i did tthis once years ago and it knackered it straight away