Electric aerial NB faulty -main fuse blow?

Technical Area Electrics & ICE
1
  1. My model of MX-5 is: NB
  2. I’m based near: ESHER
  3. I’m looking for technical help or recommendations on: ELECTRIC AERIAL PROBLEM

Need your kind help again people.
Have issue on electric aerial just fitted

Received a second hand electric NB aerial , plugged the 3 wire connector in.
(Car was fine few days ago.)
Turned ignition key… nothing…no electrics ,no lights wipers or interior light…not starting etc…zilch ! :relaxed:
Double checked battery. All good.test shows 14v
Car was fine few days ago.
About to go and buy some fuses specifically for room fuse 10, 20 amp etc. 40 amp fuse under bonnet - 80 amp ??

My question is : could the ’ Main 80amp protector fuse have blown just from connecting the connector to this aerial?

I’ve not checked or replaced any fuses

Would have expected something to be still active. Definitely not battery.

(And no - I have not done any wiring project - as suggesting in previous message - that will be for another time.)
Brian

2

I’m pretty sure the aerial is fed from the room fuse ( 10 amp ? ) so if thats blown pretty much everything in the cabin will be dead. The 80 am fuse should still be intact as the room fuse should have failed long before.
D

3

Replaced 10amp fuse, battery full charge, but still nothing- no ignition, no instruments, etc
Can’t see what else - the 80 amp fuse I can see the 2 bolts - removed negative terminal first, but can’t get to the bolt after removing plastic snap plate. Is there a trick or special spanner - ?

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4

So was the 10 amp fuse blown?
If it had blown have you checked it since you replaced it to see if it’s blown again? Do you have a test meter or can you borrow one. I’d still doubt the 80 amp fuse would have gone unless something else shorted.

5

Hi thanks for reply.
10 amp fuse was not blown after testing original, but replaced anyway.
Agree it shouldn’t be the 80amp - if I use multimeter on those 2 bolts securing 80amp- that should indicate broken or not, right?

6

Don’t just measure resistance across the fuse as there are too many things connected to it.
if you use the meter on DC volts, with the negative probe on a good earth, you should get 12 volts at both ends.
D

7

Oh, yes of course. Can’t get the fuse out still
Thanks again :point_up:

8

Just another quick thought.
Do the brake lights come on when you push the brake pedal? If they do I’m pretty sure that means the main fuse is okay.

9

Thanks for the added help and thoughts, after double checking. the battery was not up to the appropriate volts for starting and instruments… The reading measured using my battery charger - 12.02v . I thought meant it’s fully charged.

Recharged on a trickle charge overnight, … Car started next day no problems, so will continue with further checking and update when resolved electric aerial issue.