74 2500M: no wipers, signals or cooling fan. What the...?
Discussion
Guys, I had my dash out to create a template for making up a wood dash.
Then, reinstalled the old one, and created some electrical gremlins.
I'm an electrical ignoramus, so I need some advice.
Wipers, signals and cooling fan are out.
An odd symptom: when I flip on the wiper switch or the panel switch, my tach cuts out.
Is this likely a grounding problem behind the dash. Or something as simple as a fuse?
Any advice on where to begin?
Then, reinstalled the old one, and created some electrical gremlins.
I'm an electrical ignoramus, so I need some advice.
Wipers, signals and cooling fan are out.
An odd symptom: when I flip on the wiper switch or the panel switch, my tach cuts out.
Is this likely a grounding problem behind the dash. Or something as simple as a fuse?
Any advice on where to begin?
Yeah I reckon that's the favourite (and most likely) choice.
Because it's all GRP, there has to be a good earth return, otherwise you will get all sorts of weird effects. make sure the metal cases of the gauges are earthed.
A simple way is to use a small bulb, connect one end to the battery +ve, and use the other as your test probe. Bulb should light up when an earth is touched - make sure brightness is the same as when it is connected across the battery directly. if it comes on dimly, you've got an earth problem somewhere.
What happens to side lights (gauges). that's a good clue too.
Test meters are VERY useful, even if you are an electrical novice !
Because it's all GRP, there has to be a good earth return, otherwise you will get all sorts of weird effects. make sure the metal cases of the gauges are earthed.
A simple way is to use a small bulb, connect one end to the battery +ve, and use the other as your test probe. Bulb should light up when an earth is touched - make sure brightness is the same as when it is connected across the battery directly. if it comes on dimly, you've got an earth problem somewhere.
What happens to side lights (gauges). that's a good clue too.
Test meters are VERY useful, even if you are an electrical novice !
Thanks guys. I solved the turn-signals -- replaced a fuse that looked ok, but apparently wasn't.
Now, it's the wipers and cooling fan. I thought the panel lights were out, but they're not -- except to the tach.
And the tach still cuts out as soon as I turn on the wipers or the panel switch.
Does it make sense that I've got a tach grounding problem of some sort? Or is that far too simple a solution?
Now, it's the wipers and cooling fan. I thought the panel lights were out, but they're not -- except to the tach.
And the tach still cuts out as soon as I turn on the wipers or the panel switch.
Does it make sense that I've got a tach grounding problem of some sort? Or is that far too simple a solution?
Renaldo said:
...And the tach still cuts out as soon as I turn on the wipers or the panel switch.
Does it make sense that I've got a tach grounding problem of some sort? Or is that far too simple a solution?
Yes. That makes perfect sense. Make sure case is earthed, some tachos have a separate earth tag as well, but some don't.Does it make sense that I've got a tach grounding problem of some sort? Or is that far too simple a solution?
I still recommend a basic test meter. Cheap, and very useful for these type of problems !
Thank you Andy and Mick. I notice my tach has a small ground post/tab sticking out from the lower back.
And sure enough, a black wire was hanging free that seemed to logically connect to it.
But when I connected it, the problem remains. Might it be that ground wire needs to be tracked to it's grounding point to ensure it has a clean connection?
And sure enough, a black wire was hanging free that seemed to logically connect to it.
But when I connected it, the problem remains. Might it be that ground wire needs to be tracked to it's grounding point to ensure it has a clean connection?
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