Melting wires under the relay box

[CJJM]

Hi guys, lovely to be here and I truly hope you can help me! I have a 1990 Volvo 480 N/A that used to be my mothers, the car was sitting up for well over 10 years. Put a battery in (after checking engine,sparks etc) to see what would happen! The lights came on and wipers etc all worked, turned the key once and all seemed well, turned the key to crank and then nothing happens,lights etc dim but no click or anything. Put in 2 new relays,one for ignition and one for starting and reconnected the battery, lights came on, turned the key once and again all was good, turned the key to crank and smoke came bellowing out from the relay box. After inspection it was clear that all the brown wires were melted and done for. I'm not sure if these brown wires were stock or botched by someone as it didn't look the cleanest of jobs but the car was in full working order before it was put up! We rewired it the exact same way with the right wire but they keep melting? We've tried earthing the battery more using jump leads between the battery and block but still nothing, we've checked everything and can't work this out! Any help would be excellent! Thanks!

[Alan 480]

there are TWO types of relay, different pin-outs

you can here

http://www.volvo-480-europe.org/forum/v ... 98#p212332

made a similar mistake once before with previous car, I'd just chucked in a relay from spares box, never checked the pin-out, the wee puff of Jo Lucas was a bit scary . . . . .

I can't remember which one goes where tho. (Brinkie will )

but if wires been replaced by previous owner , maybe they'd made same mistake?

[eye of ra]

I would certainly do as Alan suggest and check the relays are the correct type.

Brown wires are earth wires.

When you say “starting” relay which one do you mean as the only relay that would stop the starter motor from turning is inside the starter motor itself, there are other relays that would stop the car from starting/running once the motor is turning but not stop it turning in the first place. Hope that makes sense.

[brinkie]

Did you check the earth wiring (the thick braided wire from the battery to the car) and the wiring to starter motor? It looks like something tried to find earth through places that weren't designed to carry that much of current.

Anyway, you have a thorough job to do now, that is to replace ALL molten wiring with fresh wiring of the same wiring gauge (or better), and to check and possibly re-make ALL connections where earthing is involved. Failure to do so may result in severe electronic gremlins which will be haunting you for years. I've had the same in a French car where the wiring shorted causing a lot of smoke and a dead car, and I thought it had been repaired. Yes they connected the wires back together, but left some of the wires exposed as the insulation has been molten away. A few years later the car electrics suddenly died in the middle of an intersection, in the pouring rain. The car had to be towed away and I had to replace all the exposed wiring.

[CJJM]

Ok sorry for taking so long just took me awhile to try and figure it out, so what your saying is that I have the wrong relays and too much power is being sent down the wire that is melting?
I changed the two relays in the middle on the left hand side (the bottom of the triangle if you understand me?) I will take pictures later today as I will be trying again!

[eye of ra]

As mentioned the 480 uses a less common type of relay so if you have changed them with the common type then they will be wrong.

Assuming I have understood you correctly, you have a UK car after 1988 and not changed the tall relay (as there are 3 in the middle) the relays you have changed are for the ABS and the fog lights.

If I am correct I would put back the original relays and assuming the smoking stops concentrate on getting the starter to turn (as well as replace all burnt wires) because if you are not getting a click when you turn the key it is going to be the relay/solenoid inside the starter motor not any relays in the pyramid.

*****EDIT*****

Think I may have miss understood which relays you have changed.

Having read your description again I think it’s the relays for numerous thinks including the alternator, instrument panel, reversing lights, heated seats, DRL, wipers, windows and a whole lot more but not the starter motor so the rest of what I said still stands.

[brinkie]

Having read your description again I think it’s the relays for numerous thinks including the alternator, instrument panel, reversing lights, heated seats, DRL, wipers, windows and a whole lot more but not the starter motor so the rest of what I said still stands.

Most relays for abovementioned functions are inside the CEM.
What you mean are the relays that are switched through the ignition key.



Relays B and C are the relays supplying power to parts that should only be on when the ignition key is turned on.

[eye of ra]

Your right I could have explained it better, the relays supply power to the list I mentioned not control.

My main point however (which may also have not come across properly) was there may be nothing wrong with the old relays as none of them give power or control to the starter motor which is the problem in the original post.

If the starter motor does not turn it is most likely the starter motor as it has its own internal relay.

It could however also be a wiring issue, the key switch or if it’s an auto the Park/Neutral switch.