faithie999
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i have a 2020 Ram 1500 Hemi. 3 times over the past couple of months i've had the following problem.
when i step on the brake pedal to start the truck, it is very stiff and barely depresses. when i press the start button, only a loud click.
battery: in Jan 2025 i replaced the original battery with an Interstate AGM from costco.
the first time i encountered this problem (early july), i suspected the battery (even though it was fairly new) so i put on my 350 amp portable booster. i don't remember how long i had it attached, but after some time the truck started.
the second occurrence was about 3 weeks ago. once again, the brake pedal was very stiff when i tried to start. again, i used the portable booster for about 30 minutes and that did the trick. i didn't think to measure the battery voltage before i attached the booster. i began to suspect the health of the battery. i returned it to costco and exchanged it for a standard lead acid battery.
the third occurrence was yesterday. same drill--stiff brake pedal, put on the charger, waited about an hour, it started. this time i measured the battery voltage before putting the booster on and it was 12.52 v which should have been sufficient, i would think. i turned the engine on and off several times without issue.
now the interesting part: with the engine off, i pumped the brake pedal a few times until the pedal was stiff, and tried to start the engine, and same issue--only a click. once again, i needed to have the booster attached for a while for it to start. again, the battery voitage was about 12.5 v before the booster, and 12.8 v (probably surface charge) after the booster was removed. (note: except for this experiment, i never pump the brake pedal when i get into the truck to start it. i just step on the pedal and it depresses an inch or two.)
the searching i've done shows this is a problem with Pacificas, which apparently have an auxiliary battery which had failed. but not the issue with the Ram.
i have read that the brake pedal might be stiff while the engine is off if the brake fluid is low. yesterday it was about 3/4" low in the reservoir so i topped it off before i ran the experiment to pump the brakes, but it didn't help.
it may be that when the issue is occurring, the brake pedal isn't depressing enough for the brake light switch to tell the computer the brake pedal is depressed when trying to start. but the question is: why would the brake pedal be stiff after the truck had been sitting since the last time it was driven (hours, or a day or two), when normally it depresses an inch or two?
thanks in advance for any thoughts.
Ken
when i step on the brake pedal to start the truck, it is very stiff and barely depresses. when i press the start button, only a loud click.
battery: in Jan 2025 i replaced the original battery with an Interstate AGM from costco.
the first time i encountered this problem (early july), i suspected the battery (even though it was fairly new) so i put on my 350 amp portable booster. i don't remember how long i had it attached, but after some time the truck started.
the second occurrence was about 3 weeks ago. once again, the brake pedal was very stiff when i tried to start. again, i used the portable booster for about 30 minutes and that did the trick. i didn't think to measure the battery voltage before i attached the booster. i began to suspect the health of the battery. i returned it to costco and exchanged it for a standard lead acid battery.
the third occurrence was yesterday. same drill--stiff brake pedal, put on the charger, waited about an hour, it started. this time i measured the battery voltage before putting the booster on and it was 12.52 v which should have been sufficient, i would think. i turned the engine on and off several times without issue.
now the interesting part: with the engine off, i pumped the brake pedal a few times until the pedal was stiff, and tried to start the engine, and same issue--only a click. once again, i needed to have the booster attached for a while for it to start. again, the battery voitage was about 12.5 v before the booster, and 12.8 v (probably surface charge) after the booster was removed. (note: except for this experiment, i never pump the brake pedal when i get into the truck to start it. i just step on the pedal and it depresses an inch or two.)
the searching i've done shows this is a problem with Pacificas, which apparently have an auxiliary battery which had failed. but not the issue with the Ram.
i have read that the brake pedal might be stiff while the engine is off if the brake fluid is low. yesterday it was about 3/4" low in the reservoir so i topped it off before i ran the experiment to pump the brakes, but it didn't help.
it may be that when the issue is occurring, the brake pedal isn't depressing enough for the brake light switch to tell the computer the brake pedal is depressed when trying to start. but the question is: why would the brake pedal be stiff after the truck had been sitting since the last time it was driven (hours, or a day or two), when normally it depresses an inch or two?
thanks in advance for any thoughts.
Ken
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