mackrmodel686st Posted December 30, 2024 Share Posted December 30, 2024 I posted over a week ago and got no responses, so I'll try again. 2015 mack pinnacle with the mp7 engine. When the key is turned to the run position nothing happens, when turned to the start position the dash turns on like the key is in the run position. When you let off the key everything turns back off. Thought that maybe the key switch was bad so we replaced it but still have the same problem. Has anyone run into this problem and could someone possibly point me in a direction to start looking. Thanks. Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/ Share on other sites More sharing options...
fjh Posted December 30, 2024 Share Posted December 30, 2024 Sorry no one has posted ! as its not that common of a compliant ! Just stab in the dark ! I would try a new ignition switch! Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565027 Share on other sites More sharing options...
Joey Mack Posted December 30, 2024 Share Posted December 30, 2024 Sounds like the wires in the plug are switched around. Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565028 Share on other sites More sharing options...
mackrmodel686st Posted December 30, 2024 Author Share Posted December 30, 2024 15 minutes ago, fjh said: Sorry no one has posted ! as its not that common of a compliant ! Just stab in the dark ! I would try a new ignition switch! We tried that already, problem still the same. Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565030 Share on other sites More sharing options...
Joey Mack Posted December 30, 2024 Share Posted December 30, 2024 Is there a gray wire on the key switch plug? That would be the ground Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565032 Share on other sites More sharing options...
fjh Posted December 31, 2024 Share Posted December 31, 2024 somthing that has come to mind that you might try is to check the ecu plug for oil these had oil push issues in the wiring harness!! 2 Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565058 Share on other sites More sharing options...
mackrmodel686st Posted Friday at 05:55 PM Author Share Posted Friday at 05:55 PM On 12/31/2024 at 9:07 AM, fjh said: somthing that has come to mind that you might try is to check the ecu plug for oil these had oil push issues in the wiring harness!! We checked that for corrosion, didn't see any oil. I've seen on the older trucks with the vmac iii engines that the coolant level sensor will push coolant, but not oil. Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565290 Share on other sites More sharing options...
Mackpro Posted Saturday at 03:12 PM Share Posted Saturday at 03:12 PM (edited) There is a ground stud welded to the frame rail behind the battery box. Check the wire from the ground stud to the negative on the battery. It’s a smaller fuseable link wire that can melt inside and cause this issue. I’ve also had the stud break loose from the frame and had the eyelet ends come looked from the cables Edited Saturday at 03:14 PM by Mackpro Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565363 Share on other sites More sharing options...
Mackpro Posted 15 hours ago Share Posted 15 hours ago I found my notes on this exact problem, “No power till you turn key to start position “. Fuse/breaker number 7 in top dash fuse box is bad or blown. The one I had used a fuse and showed 12 volts on both sides( key off) but when turn key to on position one side of the fuse dropped to 2 volts 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565675 Share on other sites More sharing options...
fjh Posted 14 hours ago Share Posted 14 hours ago 39 minutes ago, Mackpro said: I found my notes on this exact problem, “No power till you turn key to start position “. Fuse/breaker number 7 in top dash fuse box is bad or blown. The one I had used a fuse and showed 12 volts on both sides( key off) but when turn key to on position one side of the fuse dropped to 2 volts Man / Mackpro you must have a Novel going by now! The shit that goes wrong with this stuff is endless! 🙄 1 Quote Link to comment https://www.bigmacktrucks.com/topic/74917-2015-mack-pinnacle-no-crank-no-start/#findComment-565679 Share on other sites More sharing options...
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