Mike285 Posted February 25, 2020 Share Posted February 25, 2020 I'm very new to the world of heavy trucks and don't have a lot of experience working on them, but I'd like to try to chase this issue down without calling in a mechanic... I've got a 1998 RD with a mechanical 350, ran fine yesterday but today just clicked when I tried to start it. I'm looking for advice on the best place to start diagnosing whether the issue is the starter, a relay, a solenoid, or something else. A few times many months ago I lost all electrical power while driving and I've read that could be the accessory relay under the dash, but that issue went away and has not be happening recently. When the truck wouldn't start today, I tried jumping the solenoid on the back of the firewall and still got the same click as when I turn the key. Should I start with the relay under the dash, or the starter, or somewhere else? Thanks Quote Link to comment https://www.bigmacktrucks.com/topic/61135-help-diagnosing-no-start-98-350/ Share on other sites More sharing options...
MACKS Posted February 25, 2020 Share Posted February 25, 2020 I would start with the batteries and all connections including the ground. Quote Link to comment https://www.bigmacktrucks.com/topic/61135-help-diagnosing-no-start-98-350/#findComment-443720 Share on other sites More sharing options...
Mike285 Posted February 26, 2020 Author Share Posted February 26, 2020 I cleaned up all of the battery connections today and ended up replacing all 3 batteries (they were 8years old anyway). That didn’t solve the problem, next I replaced the solenoid on the firewall that was clicking when I turned the key...still no luck. I’m thinking the next step would be the starter, but I don’t want to replace the starter without knowing if that’s the issue. Any suggestions? Quote Link to comment https://www.bigmacktrucks.com/topic/61135-help-diagnosing-no-start-98-350/#findComment-443800 Share on other sites More sharing options...
alex g Posted February 26, 2020 Share Posted February 26, 2020 I had similar in my R model. It was the starter. Can you jump the solenoid on starter itself? Quote Link to comment https://www.bigmacktrucks.com/topic/61135-help-diagnosing-no-start-98-350/#findComment-443805 Share on other sites More sharing options...
Mike285 Posted February 27, 2020 Author Share Posted February 27, 2020 It appears I’m not getting power to the small positive wire on the starter solenoid when I turn the key. I’ve got constant power to the big positive terminal, but the small “exciter” wire doesn’t power up when I turn the key to start the truck. So somewhere between the ignition switch and starter I must have a broken wire or bad connection? I tested the ignition switch and it appears to be good. thanks Quote Link to comment https://www.bigmacktrucks.com/topic/61135-help-diagnosing-no-start-98-350/#findComment-443903 Share on other sites More sharing options...
fjh Posted February 27, 2020 Share Posted February 27, 2020 Check you have power on both sides of the firewall relay just cause it clacks don’t mean it’s working! just saying Quote Link to comment https://www.bigmacktrucks.com/topic/61135-help-diagnosing-no-start-98-350/#findComment-443917 Share on other sites More sharing options...
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