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Discussion Starter · #1 ·
Hey there - this is my first post after signing up yesterday. This is my second SAAB; the first being an '86 2 door coupe / 5spd in college, which I had for three years. I've spent the last twenty years restoring VW's and Porsches, and most recently, my '78 Mercedes 280ce. I picked up a '91 900S Convertible 5spd from a neighbor for 500.00 yesterday, and it has a few electrical gremlins (surprise, surprise).
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The most concerning of them is that the positive cable from battery to starter had long ago melted the insulation at the starter, and the battery gets very hot (PO has a fairly new Optima Red installed, that I think is junk because of this problem). Car doesn't appear to be charging, as there's barely 12v at idle at the battery. The melted cable is corroded and I'm sure has extraordinarily high resistance. My question: would this cause the battery to overheat? See photo below:
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I ordered a new wire this morning and once installed, will test to see if the (replaced last year) alternator is functioning, before continuing with diagnostics.

Any other conditions you can point towards that would have been the root cause of this overheated/melted wire from battery to starter?

Looking forward to digging in to the Art of SAAB maintenance again. They are such easy cars to work on, compared to others I've had.

Thanks in advance for your wealth of information.
Greg, in Orinda, CA

saab - 2.jpg
 

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I think I recognize you from comments on Bring a Trailer, welcome!

It looks like the cable definitely should be replaced, but I'm wondering if your actual problem is the alternator. I say you're on the right track - replace the cable and test the voltage at the battery again.

I had the one in my 91 900t rebuilt by a local shop two years ago. I never noticed the battery getting hot, but I had the same issue with a little less than 12v across the battery while running.
 

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Discussion Starter · #3 ·
Hey there - thanks for writing. Yup, that's me. Surprised by that 900T's 23k fetching price, for sure! It's just a few miles from me, actually. Yeah, we'll see where the rewire takes things, and curiously, there's a new starter in the trunk. Perhaps the starter is having troubles and a low-voltage cold start over-cranking could have caused the initial wire damage.

This battery was actually starting to smoke - car had been running for about 1hr. Before I brought it back to the seller's house, I let things stabilize in my driveway and kept my distance until I could safely remove it (wearing welding gloves, a welding vest and full-face protection with my plasma cutting shield. Didn't want the thing to pop. I dropped a spare battery out of my disassembled VW THING into it and it started right up. Strange, indeed, but I'll get to the bottom of it.

I think I recognize you from comments on Bring a Trailer, welcome!

It looks like the cable definitely should be replaced, but I'm wondering if your actual problem is the alternator. I say you're on the right track - replace the cable and test the voltage at the battery again.

I had the one in my 91 900t rebuilt by a local shop two years ago. I never noticed the battery getting hot, but I had the same issue with a little less than 12v across the battery while running.
 

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I agree that the cable is really the only place to start but would also recommend that you go around and clean many of the grounding connections.

I really don't know, maybe someone else does if the non-turbo cars had a heat shield protecting the battery. It appears yours does not. The turbo cars did but the turbo sat only a few inches away from the battery and you have way more clearance on the NA version. That's probably not your issue.

Lastly, are there any weird accessories added to the car like poorly installed stereo equipment that is not properly fused?

99% sure the issue is in the cable but think the grounds are worth cleaning on any used car you buy.
 

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Both good points about the grounds and the heat shield.

I don't know about the 91 NA cars, but I had a 85 NA that had a smaller shield, exactly like what's pictured on this car. It didn't have the insulation material that the shield on my 91 turbo has. I think it's main purpose is to hold the battery in place.
 

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Discussion Starter · #6 · (Edited)
Hey All - thanks for your input on the melted wire / hot battery issue.

I ordered a new cable kit that connects the battery to the starter and the distribution block on the right fender, installed it, and from that point on, got 13.9v at the battery with the car at idle - with no measurable difference between the terminal on the alternator (replaced by previous owner).

Everything seems to be working fine now with the charging system and there's a lot more current going to the starter.

Next up: heater valve replacement!

UPDATE: turns out the heater control knob was disconnected from the valve. 10 minutes later: FIXED!
 
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