Malvern newbie electrical issues

[jaglover842]

Hi,

The Series 2 1970 Roadster is on the road (taxed and MOT'd). Having recently acquired this, I have started to tinker with a few electrical issues the car has had.
I have been left with a number of Service Manuals etc. but not sure they are exactly for this model.

In summary, these issues are:

Rev meter is on steroids (bouncing all over the place)
Speed indicator reads too low (I estimate by about 10 to 15mph)
A red light always stays on on the dashboard
The horn does not work
The dip/main beam lights no longer work - but side lights do.

Taking these in turn, the rev meter was like this after the MOT. Anyone know what's causing this?

Any one know why the speedo is too low or what might cause this?

There is a large lamp next to the Headlamp Dip switch which is always on (red). This seems to be Handbrake/Brake Fluid Level warning light. Handbrake and braking are OK though.

I have physically relocated the alternator and horn relays. The alternator relay had a dislodged connector on C2 which resulted in battery not charging. Fixed now, combined with tightening up the loose alternator belt.

What tightness should the alternator belt be (how much should it deflect by)?

I had to use cable extensions when relocating the horn relay. All connections are tight and and are correct compared to before the relay's move. Colour coding in the Service Manual also agrees with the connection points. Anyone know why both horns do not work? I never tried the horns before the move, but I assume they must have worked to pass the MOT back in November.

I have tightened up the alternator belt, but there seems a lot of play in the main belt. This one has a pulley which I assume regulates the tension. How much deflection should be in this belt when the engine is off?

Are all the fuses in the car contained in two separate boxes behind the dash? How do I get access to them to see if any are blown?

Oh yes, I have been advised to get a new oil pressure sensor - the mechanic says it was reading a bit low during the MOT.

Has anyone successfully fitted a concealed isolator switch to these cars for security?

You should be able to spot that I am relatively new to doing jobs on the E Type, but I really want to get my hands dirty.

Any help is appreciated.
Thanks.