DBGraves Posted March 4, 2023 Share Posted March 4, 2023 My truck has a override switch. But I can’t get it to work does something have to be done in the Ecm to make it work. It’s a Vmac 3 E7 400 thanks in advance Quote Link to comment https://www.bigmacktrucks.com/topic/72562-99-rd688s-cooling-fan-override-switch/ Share on other sites More sharing options...
0 880joe Posted March 4, 2023 Share Posted March 4, 2023 On my CH's I believe the override switch is for engine shutdown. It overrides for a short amount of time to get you off the road 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72562-99-rd688s-cooling-fan-override-switch/#findComment-526425 Share on other sites More sharing options...
0 DBGraves Posted March 4, 2023 Author Share Posted March 4, 2023 Is it a silver push button with a round red override label around it Quote Link to comment https://www.bigmacktrucks.com/topic/72562-99-rd688s-cooling-fan-override-switch/#findComment-526428 Share on other sites More sharing options...
0 880joe Posted March 4, 2023 Share Posted March 4, 2023 No it's a rocker switch that looks like all the other switches Quote Link to comment https://www.bigmacktrucks.com/topic/72562-99-rd688s-cooling-fan-override-switch/#findComment-526430 Share on other sites More sharing options...
0 DBGraves Posted March 4, 2023 Author Share Posted March 4, 2023 I got you. In my RD688s the only rocker switches I have is for cruise control. The rest of mine are just toggle switches. But I still think your right about my override switch. reason I was asking was my truck doesn’t have a fan override. Talked to Mack yesterday and they say it’s already wired in in the harness just have to find the wires. So then came home looked in the truck and see that. I was hopeful it was already done. Haha. Thanks for your time. And wisdom Quote Link to comment https://www.bigmacktrucks.com/topic/72562-99-rd688s-cooling-fan-override-switch/#findComment-526432 Share on other sites More sharing options...
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DBGraves
My truck has a override switch. But I can’t get it to work does something have to be done in the Ecm to make it work. It’s a Vmac 3 E7 400 thanks in advance
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https://www.bigmacktrucks.com/topic/72562-99-rd688s-cooling-fan-override-switch/Share on other sites
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