Speedo stopped working and alternator died
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Tuned
Joined: Jan 2015
Posts: 453
Likes: 81
Speedo stopped working and alternator died
Guess I know what I'm working on this weekend.....
About 45 minutes into an hour long trip and I get that burning electronics smell. Nothing that I notice seems to be affected, and I wonder if it's really some low-level semi truck brake odor as I'm surrounded by other vehicles on the Interstate. I open the windows more to let the smell dissipate and am really at 80/20 that it's my truck, but have nothing to prove it.
On the way back (another hour) I notice that the speedo isn't working and the odometer is blank, but all the other gauges are working, as well as blinker lights. I had been running in the low 80's for several miles earlier, if that matters. I don't get Betty Sue out on the open road much, so this isn't her regular commute, though I do drive her a few times a week for groceries and other errands. No other electrical issues recently and I haven't installed anything new or even opened the hood in several months.
I then notice my voltmeter is lower than normal, not that I know exactly where 'normal' is. The needle is now over the first vertical in the N. I just know that, usually, it's higher. I also see that the battery indicator light is on. It's not super bright and with shades on it wasn't readily apparent earlier though I bet it's been on since the smell occurred.
The engine is revving higher now before shifting, but once the shift happens it holds it, and the OD light isn't doing anything weird.
I'm watching the voltmeter steadily and it stays at the N or just below it until I finally make it back to town. As I hit loop traffic the needle drops more quickly down almost to the 8 and I finally get some mistiming/misfire burps from the engine and pull over. I call my son and he tows me home. I hook up the battery charger and it's pushing 16 amps so the battery is certainly drained. I'm amazed that I was able to drive a good 60 miles or so on just battery power, or so it seemed. Is this normal?
The symptoms certainly point to a failed alternator, but I saw no burnt wiring or smoke residue doing a cursory inspection of the battery/alternator area. Not sure if the speedo/odometer thing is related or coincidental. I haven't checked fuses, but I'll do that tomorrow when there's daylight. I'll also do a better inspection of the wiring and check alternator output once I have a charged battery to start it with.
I have a gauge module out of a 96 that I can swap in. Hopefully the issue with the current one will be obvious when I look at it. I've heard there's a capacitor that can leak. Maybe it's that simple.
Would any of you have helpful thoughts on dealing with this one?
About 45 minutes into an hour long trip and I get that burning electronics smell. Nothing that I notice seems to be affected, and I wonder if it's really some low-level semi truck brake odor as I'm surrounded by other vehicles on the Interstate. I open the windows more to let the smell dissipate and am really at 80/20 that it's my truck, but have nothing to prove it.
On the way back (another hour) I notice that the speedo isn't working and the odometer is blank, but all the other gauges are working, as well as blinker lights. I had been running in the low 80's for several miles earlier, if that matters. I don't get Betty Sue out on the open road much, so this isn't her regular commute, though I do drive her a few times a week for groceries and other errands. No other electrical issues recently and I haven't installed anything new or even opened the hood in several months.
I then notice my voltmeter is lower than normal, not that I know exactly where 'normal' is. The needle is now over the first vertical in the N. I just know that, usually, it's higher. I also see that the battery indicator light is on. It's not super bright and with shades on it wasn't readily apparent earlier though I bet it's been on since the smell occurred.
The engine is revving higher now before shifting, but once the shift happens it holds it, and the OD light isn't doing anything weird.
I'm watching the voltmeter steadily and it stays at the N or just below it until I finally make it back to town. As I hit loop traffic the needle drops more quickly down almost to the 8 and I finally get some mistiming/misfire burps from the engine and pull over. I call my son and he tows me home. I hook up the battery charger and it's pushing 16 amps so the battery is certainly drained. I'm amazed that I was able to drive a good 60 miles or so on just battery power, or so it seemed. Is this normal?
The symptoms certainly point to a failed alternator, but I saw no burnt wiring or smoke residue doing a cursory inspection of the battery/alternator area. Not sure if the speedo/odometer thing is related or coincidental. I haven't checked fuses, but I'll do that tomorrow when there's daylight. I'll also do a better inspection of the wiring and check alternator output once I have a charged battery to start it with.
I have a gauge module out of a 96 that I can swap in. Hopefully the issue with the current one will be obvious when I look at it. I've heard there's a capacitor that can leak. Maybe it's that simple.
Would any of you have helpful thoughts on dealing with this one?
Laughing Gas
Joined: Oct 2025
Posts: 1,235
Likes: 254
I would definitely start with testing the alternator. The electrical smell could be from inside the alternator with no visible markings. Once you know that was good, then look at the dash if gauges don’t return.
Cross-Country
Joined: Mar 2024
Posts: 90
Likes: 7
From: MN
Fun stuff. Check if your alternator is charging correctly with multimeter. I would clean some grounds as well. Hope that smell wasn't your computer. Could've blown a capacitor... Maybe I might be talking out of my butt. Lol.
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