Very strange electrical problem.

[gusu]

So for some time now my lights dim when running the heat after the car has been idling for a few seconds.

Now I do have a idle surge that I'm hoping to fix very soon but I'm not 100% sure that is making a big difference.

I replaced the alternator recently and its working GREAT, the battery is also a year old and is getting fully charged.

I am also having a strange no start problem where I get in my car after having it sit over night and the battery SEEMS to be nearly dead. I mess around with the battery terminal and it acts as if it fully charged all the sudden. But the terminals are VERY clean and making good contact.

Last night I also started noticing a humming sound that gets louder when I turn up my speakers with no music on, but it is no longer doing that today.

Here is the weirdest part. If I actually let my lights continue to dim by not turning off the heat my car will eventually seem to lose power and die. But I can turn the key to the off position then turn the power back on and with out starting the car my battery is back to full power, easily powering my headlights, fog, heat, stereo, and even my defrosters.

Another odd thing is if I turn it on after I have stopped it does not do it. It's only if I have it on BEFORE coming to a stop that it will ever do it!

The worst part is I am 100% newb on wiring. I recently learned how you are supposed to properly splice wires.

Any ideas as to where to start?

 

[kchaazz]

First, Id check terminals. You said they are clean, however, what about the posts on the battery? Also, are the teminals tight enough on the posts AND the nuts which secure the wires to the terminals, and are THESE contact points clean as well? Next, go to your alternator belt and inspect it for wear, also, is the belt tight enough? The dimming of the lights may be occuring due to the idle speed dropping too far when you turn on the heater. Does it squeal when you turn on the heater and or headlights? If its squealing, the belt is slipping but also the belt can sometimes "silently" slip, so check the belt tension, I believe if you push down on the top of the belt, between the alternator and water pump pullies, you should only be able to push it down about a half inch or so. Is the battery tied down via the factory hardware? Also, check the underside of your hood, the portion that is over the battery for "arc" marks, which indicate that the terminals have contacted the hood at some point or another (this can only happen if the battery isnt tied down OR if incorrect aftermarket terminals have been installed)

 

[Chuck981]

Make sure lugs are tightened to the battery cause they can get loose.

 

[gusu]

Everything is cleaned up. I sprayed some acid detector on everything and it didn't show any signs of build up.

The alternator belt is about a weeks old and its tightened with in the range its supposed to be. It is also not squealing at all.

I forgot to mention this. Whats odd is it will only ever start my car TWICE and EXACTLY two times before it goes and does its BS. I don't even lose power when I move my terminal around, I'll have constant power but yet it does it.

When my car wont start I also hear a clicking sound. One of my friend's said it sounded like a relay several months ago but it totally went away until today.

Could it be a bad relay causing ALL of these symptoms or possibly a ground wire? I don't know much about wiring but to me it sounds like its building resistance and when I move the terminal around on the post it may be discharging some of that resistance that had built on the line.

 

[Justin_l_]

I'd check and clean all your grounds. Sounds like a weak grounding point.

 

[gusu]

I'd check and clean all your grounds. Sounds like a weak grounding point.

Sounds like a good idea to me. Which ones should I check?

 

[Justin_l_]

Sounds like a good idea to me. Which ones should I check?

I would start at battery ground and main engine ground and go from there.

 

[standard235]

These have a ground from the transmission to the chassis, the intake manifold to the chassis, and from the battery to the chassis.

I would add a ground strap to the throttle body bolts as well and make sure they are all clean and tight.

 

[gusu]

These have a ground from the transmission to the chassis, the intake manifold to the chassis, and from the battery to the chassis.

I would add a ground strap to the throttle body bolts as well and make sure they are all clean and tight.

I got new battery terminals just to play safe. I found all of the grounds except for the throttle body ground just from looking over to find any hacked or exposed wires. Everything looked good so I'm still not too sure whats going on.

I did notice Lucas gave me some pretty braided lines when he did my transmission rebuild though

 

[rimmbrme]

Since you did all the simple checks like battery terminals and ground terminals, next thing i would do is do the wire harness wiggle test. Sounds like something is getting loose or just barely touching. with the symptoms in full effect, wiggle each wiring harness/connectors (engine bay and interior) (even the fuse box assembly) you can get your hands on, and pay attention to what the car is doing (do it slowly and one at a time, don't use both hands AND watch out for hot and moving parts!) if you wiggle a harness or a connector and starts acting up or get better, you can isolate the problem (or atleast fix whatever needs to be fixed first)

I'd also get the history on the car if it's available to you, and see who has worked on your car/ what has been installed and replaced also. it's going to be helpful in the long run.

You can rule out parasitic draw since you say that when you play with the battery harness it acts like its fully charge back again.