Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Haunted speedometer and radio

It turns out that while I am driving or just idle, al of a sudden the speedometer shoots up together with the volume of the radio and the headlights shine brighter. The engine RPM’s remain the same. Also, when I am going downhill and put in neutral (this is a stick shift car) to save some gas, the car suddenly turns off.
Dunow if things are related but I would appreciate your opinion.
I am located in Catalunya, Spain, middle of the Pyrenees

I would highly suggest you stop doing this. The amount of gas you save is negligible, but if there was a sudden accident in front of you, you wouldn’t be in gear and be able to take evasive maneuvers.


I wrote the comment asking for a response explaining potential causes for the symptoms detailed.

All other comments will not be of any help.


Considering you also said:

I would consider that a huge safety issue, so don’t disregard my advice listed above. Have you taken your car into a mechanic yet? Is your check engine light on and (if so) have you had the codes pulled? Also, could you provide the year of your focus as well as how much millage (km is fine too since you’re in Spain, we can convert!) is on the engine? More details would be quite helpful before you start shooting down all other posts


I am not disregarding your safety advise, yet I much appreciate a response that could guide me towards resolving the problem.
Ford focus 2002, 220.000km and no engine light turning on the dashboard.
The mechanic got nothing when he connected the car to the diagnostic reader.
I am not letting it run on neutral downhill anymore because if the safety risks but I am curious to know if this symptom in combination with the others mentioned can be resolved before they turn into a mayor engine problem that will empty my pockets at the mechanics’

You should buy a digital voltmeter to stick in the cigarette lighter and see if these episodes are accompanied by voltage spikes (indicating a voltage regulation problem).


to elaborate on this, $8 at

Monitoring the battery voltage as posted above is a great idea. That would explain the radio, speedo , and headlight involvement, as the headlights are almost certainly on a different circuit than the radio and speedo, so it must be a problem with the voltage changing that affects both. Could be the alternator though, rather than the battery. Check your alternator belt tension. Whatever the problem is, it will probably get worse eventually, and then will be easier to figure out, that’s your upside to an otherwise frustrating problem.

The car turning off while coasting might be an ignition switch problem. Try driving with just one key installed, not a set of keys dangling. If that helps, replacing the ignition switch is the next step probably. It could also just be the engine is stalling out b/c it isn’t running well, but if that was the case it would stall out when idling, waiting at stoplights too. Does it?

How’s that Catalan independence vote going?

Thank you George for your reply.

The mechanic checked the battery and it is working fine in power as well as regulating voltage. He did not check the alternator belt tension though.

In relation to the car turning off while riding on neutral, it only does it while moving. During idling it does not happen.

Independence vote took place today but I am only residing here so I cannot vote.

I will look into the alternator belt then and accept the turning off problem for what it is, hopefully it does not turn into some mayor engine problem.

Take care!


already had that checked and there is no problem in voltage

thank you though for taking the time to respond

take care!

already checked and no voltage problem revealed

Thank you for taking the time to respond though

take care

You need to monitor the charging system voltage when the problem occurs, when you see the light get brighter. How long did the mechanic drive the car? Did he witness the problem?

It seems that you have a charging system problem and the belt is an unlikely cause, if the belt were loose you would be complaining about the noise.

Agree. It appears you have a voltage “regulation” issue. Not necessarily a battery issue but whatever is determining the rate of charge being sent to the battery. Some cars have the regulator as part of the alternator and others have it in the computer, but I think that’s what’s going haywire. Whether that’s why it stalls who knows but probably unrelated and a second problem.

I thought they weren’t allowing a vote over there though? Confiscating ballots and threatening?

Crazy electrical problems are many times traced to a faulty chassis ground.

thank you for taking the time to respond

I will take a closer look at the voltage regulator then

take care!