Wonder if anyone can provide insight into an odd electrical issue I experienced recently. I was riding in a 72 Cadillac like the one I used to own many years ago and it had some electrical problems. Short in the blower motor which kept blowing out the vents slightly even when climate control was turned off and the dash lights wouldn't come on but the one that perplexed me most was the indicators.

When I indicated either left or right I initially though the indicators were non-functional but it turned out that they did in fact work but only every twenty seconds or so. By which I mean that about every twenty seconds they would blink once and then nothing, the lights were steady for about twenty seconds then another blink etc. (I was driving at night so the lights were on). So basically for whatever reason the indicators were just unbelievably slow.

Any idea what can cause that? Ive seen indicators on either side flashing hyper-speed if a bulb is out on a that side but I've never seen them work at a snails pace before.

- Peter.

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2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S

Have you ever replaced the flasher relay?

No my car so no. But would that likely be the culprit? I guess it could be but I'm not an electrician so curious.

- Peter.

__________________
2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S

That's the most likely culprit, provided the voltage was up.

I recently had the turn signals on the 300SD begin to slow and sound like they might fail to flash. Replaced $30. relay and all is back to normal.

Speaking to the blower motor, a lot of older American cars had blowers that couldn't be turned off 100%. This was by design to prevent exhaust buildup in the interior.

Older cars (and a few newer ones) use a load based flasher. You can buy a solid state replacement that will flash at the same rate regardless of the load.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

Every older GM I have owned was that way.

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On some nights I still believe that a car with the fuel gauge on empty can run about fifty more miles if you have the right music very loud on the radio. - HST

1983 300SD - 305000
1984 Toyota Landcruiser - 190000
1994 GMC Jimmy - 203000

https://media.giphy.com/media/X3nnss8PAj5aU/giphy.gif

Interesting. So that means that if the key in the ignition but switched off and the climate control fan is in the off position and there still is a very faint breeze coming out of the air vents this is correct?

- Peter.

__________________
2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S

GM started doing that with the blowers around 69 or 70. I find it irritating. I've owned a couple and tapped a switch into the blower circuit to stop it. I thought it would wear out the blower motor much more quickly. Also, it could be that someone towed a trailer with the car and put in a heavy duty flasher to slow down the rate with lots of lights in the circuit.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Fan should only come on with ignition on. Off and everything should be off.

__________________
On some nights I still believe that a car with the fuel gauge on empty can run about fifty more miles if you have the right music very loud on the radio. - HST

1983 300SD - 305000
1984 Toyota Landcruiser - 190000
1994 GMC Jimmy - 203000

https://media.giphy.com/media/X3nnss8PAj5aU/giphy.gif

Definitely no towing with this car. That much I do know.

- Peter.

__________________
2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S

That's what I figured. But to be honest I'm now not certain that the ignition was actually off. I might have had it in the first detent while this was going on.

- Peter.

__________________
2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S

No. If the ignition switch is in the "off" position, the blower should be 100% off. I wonder if the ignition switch may be at fault. Can any other electrical components that would normally be inoperable with the ignition switch off be operated?

Unfortunately I don't know which components on this car that would relate to. It's been 16 years since I owned one and the test was rather hurried.

- Peter.

__________________
2021 Chevrolet Spark
Formerly...
2000 GMC Sonoma
1981 240D 4spd stick. 347000 miles. Deceased Feb 14 2021
2002 Kia Rio. Worst crap on four wheels
1981 240D 4spd stick. 389000 miles.
1984 123 200
1979 116 280S
1972 Cadillac Sedan DeVille
1971 108 280S