About 10 years ago, when I worked at a dealership, I was thinking of buying
a used car from them. It had an intermittent problem, I don't remember what
it was, and they hooked up a portable diagnostic computer while I drove the
car home and back the next day. it would store history. If that was 10 years
ago, I am suppressed that your dealer can't do something like that.

I hope that you are not paying them for anything that does not solve the
issue.

Ted

"Greg"  wrote:                           (2005 F-150 Electrical Problem)

Randomly my lights, inside and out will dim for aprox 5 seconds and then go
back to normal, the blower will slow also if it's on.  I have tried to shut
off everything  and this still happens. The dealership has changed the
battery, (because it was a little low??) but can't find anything else wrong.
I notice this more at night, steady highway driving, sometimes at a stop
light, but basically random.

Isn't there something that can be hooked up, say via the cigarette lighter,
to monitor and log the voltage? My dealership says there isn't, but I have a
volt meter that will show peak voltage, you'd think they would have one that
could do low or high voltage. They said the monitor won't log in the
electrical system.

I'd think that there is a problem in the charging system, maybe the
alternator is overloading and shutting down for 5 seconds, so I am
going to battery power then back to alternator. But I don't know, I'm
not a auto mechanic. But I have mentioned it to the service manager,
but he says that if he can't replicate it he doesn't know what else to do.

They have the truck now, overnight, and will probably call me in the morning
to tell me they can't find a problem, but it's still going to be a problem
it has for the last 2 years off and on.       Help Please!!!
__________________________________________________________

Alternator brushes worn, low spring pressure, unreliable contact.

Good luck.

Rodan.

Voltage recording is possible.  I have a voltmeter wth a serial port.  I can
hook it to a laptop computer and start a terminal program to log output from
the meer.  I'm sure there are other products which can do this as well.