John3406 Posted June 6, 2021 Share Posted June 6, 2021 2002 ch with e7 427. Its cutting out as im driving it. Seems like its random but more prevalent when hitting big bumps. Its like you shut the key off for a second. It dies,the alarm comes on then takes right back off. Cleaned every ground i could find. Pulled every wire i can. Still keeps doing it. Any advice where to check next. Also tried 2 different ecm to rule that out. Thanks. Quote Link to comment Share on other sites More sharing options...
Popular Post Dirtymilkman Posted June 6, 2021 Popular Post Share Posted June 6, 2021 Relay in dash. Looks like a Ford starter relay. 3 Quote Link to comment Share on other sites More sharing options...
John3406 Posted June 6, 2021 Author Share Posted June 6, 2021 13 hours ago, Dirtymilkman said: Relay in dash. Looks like a Ford starter relay. Ok thanks ill check that out. My older RDs and superliner has a relay in the dash but i wasnt aware the newer macks used had it too. Learn something new everyday i guess. Thanks again. Quote Link to comment Share on other sites More sharing options...
John3406 Posted June 7, 2021 Author Share Posted June 7, 2021 There is no relay in the dash. Looked everywhere Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted June 7, 2021 Share Posted June 7, 2021 Then some one has removed it. Quote glenn akers Link to comment Share on other sites More sharing options...
Joey Mack Posted June 7, 2021 Share Posted June 7, 2021 Go to the fuse cover and open it... look to the left just under the center dash. there should be a bank of relays there... 3 or 4... 1'" black cubes... one of them is the "new" back then..... Acc. Relay...... you can switch the headlight relay to see if this is your issue. BTW: did you tighten the block ground on the left side, and is the ground breaker on the fire wall, good and tight? Quote Link to comment Share on other sites More sharing options...
John3406 Posted June 7, 2021 Author Share Posted June 7, 2021 I changed all 4 of the relays. And i put a new ground breaker in a week or so ago and its still doing it. Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted June 7, 2021 Share Posted June 7, 2021 codes? did you drop the right kick panel and check the v.e.c.u. connections?. Quote Link to comment Share on other sites More sharing options...
Jamkar Posted June 7, 2021 Share Posted June 7, 2021 Does it have a battery isolation switch? I had a bad one doing similar things once. Also had one with a loose cable coming off the back of it, only played up sometimes... 1 1 Quote Link to comment Share on other sites More sharing options...
John3406 Posted June 7, 2021 Author Share Posted June 7, 2021 I didnt pull the right kick panel but i will try that. Also it doesnt have battery isolation switch. I had someone drive it and i held my hand on the 4 relays in the dash. When it cuts out those relays are clicking so must be losing power to them. Quote Link to comment Share on other sites More sharing options...
fjh Posted June 7, 2021 Share Posted June 7, 2021 3 hours ago, John3406 said: I didnt pull the right kick panel but i will try that. Also it doesnt have battery isolation switch. I had someone drive it and i held my hand on the 4 relays in the dash. When it cuts out those relays are clicking so must be losing power to them. check the power supply into the fire wall drivers side! 1 Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted June 8, 2021 Share Posted June 8, 2021 ground's, ground's, ground's....😉 Quote Link to comment Share on other sites More sharing options...
Vmac3 Posted June 8, 2021 Share Posted June 8, 2021 Sounds like infamous Power rest without key switch code. There is a connector on top of the transmission clutch housing that may be loose. Wiggle that and see what happens. V Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted June 8, 2021 Share Posted June 8, 2021 9-2 code... "V"... you got this!... Glad to see you again... Hadn't seen you much lately.. well at least what I'm posting in.. Jojo Quote Link to comment Share on other sites More sharing options...
John3406 Posted June 8, 2021 Author Share Posted June 8, 2021 Ok guys thanks for the ideas. Ill look at all that was mentioned and get back to ya Quote Link to comment Share on other sites More sharing options...
theakerstwo Posted June 8, 2021 Share Posted June 8, 2021 1 hour ago, Joey Mack said: ground's, ground's, ground's....😉 You cant get too many grounds on a truck. 1 1 Quote glenn akers Link to comment Share on other sites More sharing options...
John3406 Posted June 8, 2021 Author Share Posted June 8, 2021 Well heres my update. I checked everything mentioned here. Big connector behind motor, checked all grounds again that i could find,power wires going thru firewall coming of starter relay on firewall. Pulled and shook every wire i can reach it never lost power and cut out. But drive down the rough roads and it cuts out. Ill keep looking Quote Link to comment Share on other sites More sharing options...
Joey Mack Posted June 8, 2021 Share Posted June 8, 2021 has fuse #40 been replaced with a circuit breaker? Its in the fuse box under the hood next to the steering column. Also, what kind of condition is the J-1 and J-2 connectors on the E.E.C.U.? Quote Link to comment Share on other sites More sharing options...
Vmac3 Posted June 8, 2021 Share Posted June 8, 2021 14 hours ago, Joey Mack said: 9-2 code... "V"... you got this!... Glad to see you again... Hadn't seen you much lately.. well at least what I'm posting in.. Jojo Thank you Joey. I watch the forum and participate when needed. You and a few others have a lot covered, I learn for yours and their experiences. Appreciate you and others on this forum. V Quote Link to comment Share on other sites More sharing options...
Vmac3 Posted June 8, 2021 Share Posted June 8, 2021 I just remembered something, Does this truck have a Qualcomm, ABS or anything else plugged into the J1939/1587/1708? If it does unplug it. Check in the fuse panel and you will find terminal studs marked 1587- and + (I believe) if someone can verify it. If it does remove any extra wires that are connected to it. You may have a module interfering with the Datalink. I vaguely remember having this issue. This check will not take long. Unplug these modules and recheck. Please be absolutely sure to have all the power and grounds checked as mentioned earlier (starter, battery, relays etc...). V 1 Quote Link to comment Share on other sites More sharing options...
John3406 Posted June 11, 2021 Author Share Posted June 11, 2021 Sorry guys i had to many other breakdowns the last couple days to work on this on. I will get back on it this weekend and let you know what i find. 1 Quote Link to comment Share on other sites More sharing options...
OldRedMack Posted June 12, 2021 Share Posted June 12, 2021 Do you have a power wire going to a trailer connection that has a bare spot and is shorting out and tripping the breaker on the firewall when you hit a bump. Had that happen to me before. Quote Link to comment Share on other sites More sharing options...
Popular Post John3406 Posted June 15, 2021 Author Popular Post Share Posted June 15, 2021 Update. 95 percent sure i got it fixed. Found 2 wires going to the vecu that has bare spots . Looked like they were rubbing on the box bolted to kick panel. Fixed wires. Taped everything up and drove it across a rough field and it never cut out. Thanks for all the ideas and help. 2 1 Quote Link to comment Share on other sites More sharing options...
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