I have a problem with my 850. About a week ago, the car started to crank very slowly during cold weather. In addition, I started the vehicle and none of the gauges moved. I shut off the car and restarted it, and all the gauges worked. On another start-up, all the warning lights came on and stayed on. Again, after a few minutes all the lights went out. The battery is only two months old and I'm not sure if I have a bad battery, or an alternator or other problem. I put the battery on a charger and everything was fine for a few days. However, today, the gauge situation happened again.


I could use some expertise to solve this problem.


Don

A DIY Volvo owner MUST own a multimeter.

Your problem is intermittent, so I would suspect a bad connection. Mostly I would suspect the field wire to the alternator, then everything that connects the battery and charging system, including the battery-to-ground and alternator-to-starter connections. A bad connection can and WILL fry your alternator, so be very sure that the field wire is good, and that the alternator has good ground and good connection to the battery (via the starter, I think).

I replaced two alternators on a 1980 240, the third survived because I added extra ground and starter cables. These can go bad even though they look okay on the outside, don't really understand this but now I'm a believer.

Good luck.

Very likely your alternator is the problem. Many parts stores will chedk it on the car at no cost.
You may also purchase an inexpensive digital multi-meter ($10 to $20) and measure the battery voltage. I borrowed the following from a BBS some time ago and it is
detailed but excellent and pointed a friend right to a bad alternator, confirmed by a parts place and the subsequent alternator replacement.

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A voltmeter would reveal more information than an ammeter for most problems. In my experience a digital multimeter can be connected as needed to occasionally check the charging system. This is much more accurate than a permanently installed automotive type meter with a pointer and crude scale.

The following checks may be helpful since you had or may still have dimming lights (including the warning lights). The battery voltage with no load (ignition and everything else off) should be 12.6 V - if at all lower, the battery may have a bad cell or an internal short.

With a load such as headlights only turned on (ignition off) the battery voltage should drop very little, e.g. to 12.2 to 12.4 V, unless the lights are left on for a half hour or more. If drop is more than this then either the battery was not fully charged at the start of the test or is becoming weak or is not holding its charge.

With the engine running there should be an overvoltage, around 13.8 to 14.2 volts (measured across the battery terminals) depending on ambient temperature (higher voltage at lower temperature), engine speed, and what electrical loads are operating. A dead charging system will not produce an overvoltage (you might read only 11.5 volts or even less) and a weak one will drop to smaller and smaller voltage, say 13 or 13.2, as various additional loads (lights, wipers, defroster) are turned on. If the charging system appears weak, it is important to check that all connections, particularly grounds, are intact and not corroded. Sometimes due to a bad connection the charging