I have a '93 Volvo 940 Turbo wagon with an electrical issue. The battery drains heavily and it stall while driving. The first thing that goes is the fuel gage, then the rpm gage and last the odometer reading goes to zero and a mile or so later the car stalls. When i change to a spare battery the car starts again just fine until that stalls too. And installing the battery gives an arc
I tried to disconnect some battery cables and found one that seems to have the short on. But the car doesn't start if i just leave that cable off.
The Battery has 4 cables coming to the pos terminal. The main cable that has the clamp attached, 2 smaller cables with just "rings" to hold them to the clamp and another larger cable that has 3 red cables into one "squarish" connector.
These cables are all original. nothing was added to the car.
The short is on the larger cable with the squarish connector. what components are on that cable? All other posts i found about a volvo stalling are mainly fuel stuff. nothing about a short. does a broken fuelpump or fuel relay also give a arc when changing the battery? Attached are the pix of the different cables and the one i hold alone is the one with the short.

 

It looks like those terminals could be cleaner, but I want to float another idea since I just had this problem and have the exact same car: the ignition switch going bad. That can play havoc with lots of things. Not too hard to change if you think it's suspect, but the part does cost about $100. I assume you ruled out the alternator.

Jeff

 

how do i check if the ignition switch is bad?

what other components should i check that hang on that "3-cable" connector (it's the connector on the pix where i hold just that one). This is the one that makes the arc when i install the battery. if i don't have that 3-cable on the terminal and then install the battery i don't get the spark but the car won't start either

As for the alternator, yes, it was my first idea i took it out and had it checked and it tested ok.

 

Have you tried to put 1 cable on at a time. If you start with the large batter cable and leave off the others then what does not work in the car. Can you drive it ? Then put the 2nd cable on and do the same. Which cable drains the battery. Once you know that then you can start eliminating components on that circuit. You must have a good size short draining the battery.

 

Yes, i tried the different cables. and that's what i tried to explain.
When you look at the photo DCAM0025.jpg (the one where i hold all the cables)
I tried to leave off all cables but the one on the right and the car would not start, i added the 2 cables to the left and the car still did not make a sound.
Only when i added the 2nd cable from the right the car would start but that is also the cable that makes it arc when i install the battery.
This is the cable i hold by itself in the photo DCAM0027.jpg
The cramp-on is pretty corroded, too. This whole connector is a 3-in-1. 3 separate red cables in one string.

 

My car always sparks a bit when I put on the battery cable because the clock is always trying to go.

It sounds like everything runs fine, but the battery gets drained. The first place I would look is the alternator. The diodes could be fused. Get that tested (I'm assuming you haven't since you haven't mentioned it). That wire probably goes to the positive terminal on the alt. I just checked my car's wiring diagram (it's older) and It looks like its the alt lead and also goes to the starter motor too. If the cars are the same as far as that wire, and your starter seems to work, it still looks like your alternator is dead.

So my conclusion is, get the alt checked if you haven't.

 

On my out-of-left-field ignition theory: do you ever get any odd behaviors like the warning bell ringing for the key when the door's open, but without the key being in? Or something else coming on seemingly by itself?

Also: you mentioned as the car stalls out your odometer reading going to zero- did you mean it just stops rolling over?

 

As for the alternator, i had it out and checked and it tested ok
as for whitebricks suggestion, no, i never had anything wired going on (beside the stalling that is)
The miles are till rolling, just the speed reading goes to zero. This comes before the actual stalling. so, i know what's ahead...
The usual warning is
1. The gas gauge goes down way to fast and then falls to zero (also, it moves when i use the break)
2. The RPM gauge goes to zero
3. the speed reading goes to zero
By then, the car starts to sputter and then just stalls.

I have the alternator checked and it is ok

 

Just out of curiosity, what test did that entail? Did you check individual diodes to see if the work only one way? Most of the time you check an alternator with the car running so you can see what it does with loads at a speed.

So the alt might be fine. That wire might go to the positive terminal on the car. That would make sense actually. You can get the car to crank, but no computer systems (FI, Ignition, etc) would work because they would have no power. I'd follow that harness until you find that main terminal. Then start branching out. That terminal feeds the ignition switch too. Whitebrick, seems to be on the right track with that. Some of the fuses are pretty hot when the car is running, so I'd look there for maybe on that is really hot of melted but so much that it makes contact.

 

i took the alternator out of the car and had it tested at autozone. according to them the test is well inside the Volvo specs... what ever that means

 

Yeah, that's how I feel about autozone. But they maybe right.

 

Any luck yet? How do the fuses look? I was also wondering about the radio suppression relay- I've not read much about them and was curious if trouble there could cause these kind of issues.

Jeff

 

no luck. i tried the cheapest fix just yesterday. got a terminal replacement, all cable are now clean... and the terminal brand new... but when installed it to the battery it still arced.
i was able to drive about 5 miles to the store... didn't stall but the warnings where there already (gas-gage didn't work) and when i came out of the store the car didn't start. this morning i went back with a full battery and was able to drive it home...
As for the radio... haven't used it in almost a yr due to that electric issue. i try not to put any load on extra... not even the heat fan - in mid west winter...

 

This is a major short. So I would take a fully charged battery and attach this 1 lead that arc's . Take a test light or volt meter and check each fuse to see what is hot with this wire. Write them down and remove all of the fuses and associated relays. Using an ohm meter ground 1 end and then interrogate each fuse on the downstream side. Battery should be disconnected and key off. Any fuse location that goes to infinity should be suspect. If all of the fuse locations are OK then go to the other side of the fuse and do the same thing.If any go to infinity then trace that circuit. Oh make sure that the end near the battery is not touching anything.

 

I got a brand new battery, now, too. the other was on the last leg it seems. It drove longer again. lets see how it goes today. i always have a spare battery in the car :P
I haven't yet figured out how i access the relays in my 93 940... i don't see any screws or so to take the radio out to get better access to the relays or bow do i get there? Don't wanna buy a baby to use it's tiny hands :P

 

i found what wire is the short... from that set of 3 it is the largest. and the car wont start w/o it. it tried this and when i turned the key all instruments lighted up, the door ajar beeped, the gas pumped made that little swish sound but when i turned the key to start it just made one click and everything went down. and when i have JUST that one attached, the lights, beeds and swish are still there. so, seems to be a major cable. i'm getting a bit affraid

 

So I'm going to recap and make sure I understand the information presented:

There are 4 leads coming to the positive terminal. 3 of them bolt to the main connector. The largest of those three sparks when you attach it.

A few things to note:

When I connect my car's battery, there's a little arm every time because of the clock. I'm assuming yours is bigger. I think that the clock runs on that same wire. So here is what I getting at, does the car kill the battery when it is not running at about the same rate? If it's not, it would not make sense for the arcing (while the ignition is off) to be linked to a rapid discharge that occurs only when the ignition is on. We would be chasing the problem in the wrong place.

If the discharge is the same with the car off, then I would do what jagtoes suggested with the key off. Find the circuits in the fusebox with power ans test them for a short. I think he got one thing wrong though, if you have a short, the resistance will go to 0, but I could be thinking wrong. I would prefer to use an ammeter on the batery wire and look for about the same amps on one of the fuses. If there's nothing in the fusebox, then the short is before that. I would think that fore the rate of discharge, something would be getting hot. Most wires would have a hard time draining the battery that quick ahead of the alternator with out heating up really bad.

Also, what is you battery gauge doing?

 

someone mentioned the 'radio suppression relay'. horrible name. its really a fuel injector relay. in the original setup, the fuel injectors were switched directly from the ECU, this meant current spikes were going down a fairly long wire from the ECU to the fuel injectors, and this created radio interference. so they put a relay closer to the injectors, so only relay power (a fraction of the fuel injector power) has to come from the ECU and this hugely reduced the radio static.

re: alternator tests. the out-of-vehicle tests done at the likes of autozone are OK for testing the alternator on its own, but what you're concerned with is that the battery apparently isn't recharging when you're driving, which means the alternator output isn't getting to the battery.

I think I'd use a digital multimeter with a 10 amp or higher mode (usually requires moving the plus lead to a different input), and I'd disconnect that fat wire and hook the meter in SERIES between the battery + and that fat wire, and you should see a lot of current. if you do. pull all the fuses and see if you still see that current.

1) if the current goes away with all fuses pulled, hook the wire up and stick the ammeter in each fuse socket til you find the one thats drawing the big current. if you locate it, see what circuits are on that fuse, and go from there.

2) if the current doesn't go away with the fuses, life gets more challenging. put all the fuses back in as none of those circuits are apparently the problem. probably time to start pulling relays, which I believe are behind the ashtray and radio on that car.

 

As for the wires that go to the terminal;
ONLY the "Fat Wire" is connected to the main connector. and that is ok
The next assembly (see photo in my first post (DCAM0025.jpg second lead from right) holds 3 cables and the largest of those is the "shorty"
When i connect ALL BUT the shorty and try to start the car it gives a short CLICK" and everything goes bad.
When i attach ONLY the shorty the instruments light up, the "door ajar" beeps.

as for the speed of drain THAT is totally unpredictable... last yr i did a road trip half across the country and it stalled only once (but i didn't use radio and only drove during the day to avoid using head lights)
all winter long it didn't stall and not it is again to 5 miles.
I added a trickle charger and have the car plugged in at all times when at home and i never drive at night or use extra equipment.
Yesterday, it was driving ok w/o stalling again.

 

Can you measure the voltage at the battery terminals while running? I went through something like this with my 965. Disconnecting the alternator drew a healthy arc, much more than the always on electronics should. The culprit was the alternator, most likely a leaky diode. My alternator also passed the Advance Auto alternator test. With the faulty alternator the voltage at the battery terminals was like 12.8 VDC with minimum load. The real clue I missed was the healthy arc when connecting or disconnecting the alternator, When I replaced it with the rebuild, if there was an arc I could not detect it.

Good Luck