MG Car Repair: ignition, buzzer sound, inline fuse

Question
hi howard, just bought an mgb convertible 1980 its stood for about 4 yrs after it was submerged in the floods  I have redone all the fluids and gas etc  but what my issue is that when I turn the key all I get is a buzzer sound and a light comes on that's visible between the top of the steering column and the bottom of the dash where the instrument cluster is, my question is what is that buzzer ?, I have read most of your other post and I am amazed at your ability to answer in such a professional way thanks.......ps the radio works as far as electrics go but nothing else but that and the buzzer sounding

Answer
Hi Cris,

There are several things that activate the buzzer, seat switch over the seat diaphragm, seat belt switch and as I remember it even activated the buzzer if the door was open with the key in the ignition. I have had several submerged cars from hurricanes while I was in FL. I found that many switches get shorted out and also relays too.

Working in a dealership we could not spend the time required to correct all the possible shorts so we would refuse to try as our labor bill would exceed the cost of a new harness and new relays. However as an owner you can probably spend the time digging out each short that can cause a buzzer or a component not to operate.

I can however tell you how to proceed. First you need a 12v test light, a volt/ohm meter, a couple of test leads with clips on the ends and an inline fuse holder with several fuses. And a wiring diagram of your car.

First make a list of everything that don't operate. Then pick ONLY ONE item to trace it's circuit. Pick the easiest circuit first. A wiper motor is not a simple circuit but a horn circuit is. I like to start at the load ("item that don't work")and work my way toward the source (Battery). Use the 12v test light to check the load first and with the guidance of the wiring diagram move to the next joint or connection and continue until you reach the battery.
This method is a 100% fix rate procedure. If you do this it is impossible to fail.

Often as you trace one circuit it will correct many of the others if not all of them. Keep in mind that the horn circuit works in reverse, meaning the horns are powered and the horn button on the end of the turn signal lever in your car is the ground for the circuit. You can short cut this circuit by checking to see if you have power at the horns. Purple wire as I remember, is powered, if it is not look at your diagram and follow it back to where it picks up the power (fuse box as I remember)(look at your diagram as my memory is fading at my age)

If you don't have a diagram let me know and I will post one on my web site for you to copy. The tools are not expensive and can be purchased most anywhere.

Let me know your progress.

Howard