Does anyone here have a clue why the double relays on my 79 cabriolet only seem to last for about 2 years? when they do stop working it seems to happen when the car hasn't been used for a while, I'm talking maybe for a week or two. It's very frustrating as when it's running it goes like a dream then a week or so later it's not starting at all. All fuses are intact just no power comes from the relay (redblue wire) to the pump whereas I get power from the starter (redblack) to the relay. This is probably the 5th relay in about 12 years and each one so far has to come from the US, very frustrating. Btw the power from the relay to the pump was checked at the relay so wire breakage is not the problem.

Depends how the relay is made. I'd think it'd be a single solenoid with dual contacts.

Crack it open and have a look see inside. It could be that the starter and fuel pump are on a common rail and the starter contact is stopping the pump contact making contactcos it's bent.

Just an idea but looking inside will give a better idea as to why they fail.

Are they just a pair of normal relays in the one box? Narva does something similar if so, are you getting new relays each time or second handies?

Each time I buy a new one as to what the rest of you are talking about

What is the relay running? Just a pump? Some of the old beemer fuel pumps can draw quite a few amps, might be worthwhile seeing if your not coming close to the rating of the relay, although I doubt it, have you got a wiring diagram to see if you can wire up a couple of conventional relays? At least they will be cheap and easy to get..

Do you have any old ones that can be rebuilt? We have the technology, we can rebuild them.

Following the diagram for J40 within the diagram then you possibly could use 2 normal relays in place of the dual relay.

Just looks like there's a resistor on the fuel pump solenoid and possibly a diode but opening a dead dual relay would confirm this.

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Originally posted by psimitar Quote: Originally posted by AA003 Quote: Originally posted by psimitar That'll be a DPDT then. No, DPDT has 1 coil and 6 contacts. (2NO 2NC 2Common) DP means dual pole so 2 solenoids and DT is dual throw so 2 contacts either NC or NO. Being an electrical engineer means I've been making switchboards wrong for a fairly long time now

And there's me thinking DP stood for double penetration!

I'm with spaceman on this one, and I'm only an electrical fitter mechanic/electrical technician/automotive technician.......

If you can fix the M-set Millennium trains then you can fly Air Force One!

No it wasn't the real Air Force One. Now that would be BS. It was just the one in the movie. However I did get an Oscar nomination for it.

Quote:

Originally posted by AA003 Quote: Originally posted by psimitar Quote: Originally posted by AA003 Quote: Originally posted by psimitar That'll be a DPDT then. No, DPDT has 1 coil and 6 contacts. (2NO 2NC 2Common) DP means dual pole so 2 solenoids and DT is dual throw so 2 contacts either NC or NO. Being an electrical engineer means I've been making switchboards wrong for a fairly long time now What a load of shit! DP = switches + & - at the same time. DT = switches between NO & NC. http://www.learningaboutelectronics.com/Articles/DPDT-relay-wiring-diagram I was a rocket scientist for NASA. They even named a spacecraft after me. Spacecraft: Lander