I have an '03 L200. For the last year or two during the winter time, heater will heat up and continually kick off and reset itself back to cool air. Also started hearing a buzz come through the speakers, the buzz also goes up and down with the engine rpm's. The dash lights flicker or pulsate steadily. In the last month the electrical system, radio and dash lights as well as headlights, flash off for a second or two whenever I turn on the blinker, hit the brakes, or use the electric windows. Sounds like a short to me, but other than that I'm clueless! Went out to start it yesterday and dash lights come on and everything's fine when key is in acc. position, but once I try to turn it over everything goes off, like total loss of power.

 

Damn tough to sort out electrical problems via the computer.

 

Spaulding --

Sounds like two problems are at work under your hood, one not too difficult/expensive to fix, but the other might be a bit pricey. One or both of your main power cables coming from your battery have become corroded internally, and can no longer carry the current necessary to start your car reliably. Have them both replaced (or do it yourself, and save a shop charge)

The "buzz" you hear through the speakers of your car suggest that one or more of the "stator diodes" inside your alternator have failed. Some people have the alternator pulled and rebuilt, but most have it replaced. You can go to AutoZone or similar car parts dealers, and they will usually test the alternator free of charge.

I'm not quite sure what to tell you about your heater, except to note that the heat comes from circulation of the engine coolant through a little radiator inside the car, and does not rely on any electricity (except for the fan) and the controls. Perhaps one of the other posters here has run across a problem like this in the past ........

 

Gonna agree with OceonArcher except before I go about replacing battery cables, I would remove and see if they can be cleaned. There is the little battery terminal cleaning thingy that looks like a giant thimble with a brush on the inside. When taken apart one part cleans and polishes the terminal and the other part cleans the cable connection. A tooth brush and soap and water along with Baking Soda to neutralize the yucky stuff and a coating of electrical contact grease or Petroleum jelly will go a long way towards maintaining the cruddy battery connections. If that can not be done, replace them with new cables. Damn the expense, those bolt on lead thingies will plague you untill you sell the car.
A bad ground may also magnify any problem with electrical noise from the alternator.
Most newer cars control the heat from the heater by mixing cold air from the outside with it. Older ones controlled the water flow.
The electronics controlling the cold air mixing may also be affected by what ever is causing the other problems too. Sounds like you are having a bad connection problem.
Another Variable, Rust, is your car rusty? If so, the ground connections going to the body could be in bad shape.
Ugh!

 

UnclJohn is right about the methods for cleaning and preserving the battery connections, but I was more concerned about the cables and their internal integrity. Side post batteries have a tendancy to leak around the point where the battery cables are connected. Some of this fluid gets under the cable jacket and corrodes (rots) the cable almost like a termite will eat up a 2x4 piece of wood. Treating the connections at the battery like UnclJohn suggests will go a long way in preserving and protecting, but eventually the cable's gonna fail

 

Thanks for the help guys. I'll be checking into this stuff and see what I can find. Battery posts are really clean, no corrosion at all showing, so I'll have to check the cables. The car is not rusty at all but where would I find the ground to the frame?? Sounds like I need to get the alternator checked as well. Last night I unhooked the battery for a bit to see if everything would reset itself, but still the same. Everything workd great in the acc. position, headlights, dash lights, radio, fan, but once I turned the key to start position everything went dead. I tried it a second time and in the acc. position the dash lights and everything flickered about five times and then went dead. Thanks again for all the input.

 

The negative lead from the Battery most probabaly terminates on the engine block or possibly because it is a front wheel drive car some where on the transmission housing. Why here, that is the closest place to the starter which uses the most current.
Generally there will be a wire, a heavy wire that goes from the engine block to the body of the car, fire wall, chassi side rails something like that which hooks up the negative leat to the engine.
This of course is older rear wheel drive thinking. Newer with transverse engine and batteries sitting around or over the transaxle there may be a multiple lead negative battery wire that fastens to the body of the car, fenderwell, and all of the others some how. That is how power gets a return path from the lights, radio and all the electrical stuff.
Where it is, I do not have the data to answer, but I suspect a possible problem with that wire.
If the car was mine I would have to start tracing out the battery leads which may be rather hard to do if you don't know where they actually go.
Plastic air cleaner parts, fuse box stuff, wiring harnesses etc. It's not fun some times becuase all of this may be in the way, but to me, I think you need to find it.
Some where
a lead to the engine and transaxle
and another from the battery negative to the body of the car.
Both going to the negative terminal on the battery.
A big wire probably and not very long.

 

Thanks unclejohn! I appreciate the suggestions!!! You're definately right about EVERYTHING being in the way of tracing the positive battery lead and the wiring harness is just a pain! Found the ground to the fenderwell and it looks real clean.

 

Make sure you find the one that goes to the engine too. They both should be in good shape. It would not hurt to disconnect them and re-connect them to insure that the contact points are good.
The down side will be to reset all of the radio settings, compass and what nots.
Although I found that my 2007 Chrysler has some way of remembering previous settings. Which is good. 'Cause this can drive you nuts.

 

Problem solved! I took off the alternator to have tested, which NOBODY could test on their machines due to it being too new. What! It's an '03. Read on another thread where a couple of guys having same problems replaced the starter and fixed all. So pulled the starter and battery to have tested. All tested good. Put it all back together and it started right up and ALL of my electrical issues have been resolved. Must of had a bad connection somewhere! Thanks again for all the suggestions guys!