DCR Posted November 27, 2013 Share Posted November 27, 2013 My brake lights are not working on my '58 B Model. I crawled around underneath it looking for broken wires, etc. found these two switches and do not know what there are. The first one I thought is the brake light switch since the one wire runs to the lights but not sure. Sent photos to a knowledgeable B model person and he has never seen the switch. I'm asking the BMT brain trust for help in identifying these two items. Quote Denny330-550-6020A "Mack Pack" Charter Member Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/ Share on other sites More sharing options...
pmolitor Posted November 27, 2013 Share Posted November 27, 2013 air pressure switches for brake lights and low air buzzer/light Quote Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-218628 Share on other sites More sharing options...
pmolitor Posted November 27, 2013 Share Posted November 27, 2013 air pressure switches for brake lights and low air buzzer/light Quote Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-218629 Share on other sites More sharing options...
DCR Posted November 27, 2013 Author Share Posted November 27, 2013 Momack Thanks got the help. I'll go back and trace the wires and then replace them making sure I have power to the switch. Hopefully I can find a replacement for the switch and have a new brake light circuit. As to the low air I'll get the lights working first. Again thanks Quote Denny330-550-6020A "Mack Pack" Charter Member Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-218691 Share on other sites More sharing options...
j hancock Posted November 27, 2013 Share Posted November 27, 2013 Any shop that deals with truck parts should be able to help you out with new switches. Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-218692 Share on other sites More sharing options...
Freightrain Posted November 27, 2013 Share Posted November 27, 2013 My guess is the broken one is the brake light switch. Yup, should be easy enough to get replacements. Quote Larry 1959 B61 Liv'n Large...................... Charter member of the "MACK PACK" Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-218696 Share on other sites More sharing options...
Maddog13407 Posted November 27, 2013 Share Posted November 27, 2013 i think the broken one is the low pressure buzzer. mine and most tractors are on the tractor protection valve teed in, for obvious reasons. I have replaced mine 2-3 times, the buzzer works for a few months then quits again, oh well. the two wire one is the brake light switch. most I have seen mounted on the treadle valve or a line behind the cab coing off the treadle valve. Quote Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-218700 Share on other sites More sharing options...
Mike Posted November 28, 2013 Share Posted November 28, 2013 And I have thought the low warning air buzzer was mounted under the dash to eliminate the corrosion from the weather. mike Quote Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-218802 Share on other sites More sharing options...
Maddog13407 Posted November 28, 2013 Share Posted November 28, 2013 the buzzer is under the dash, the switch for it is plumbed into the air line off the tractor protection valve behind the cab or on dump trucks its on the firewall usually by the junction block for air. that's why there is two wires going to one side of the buzzer. one or the other is dead dpending on weather it was plumbed for a tractor or not. least that's what I have seen in most of the B's I have worked on, but they do teach me something new everyday. Quote Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-218822 Share on other sites More sharing options...
felicello122 Posted November 29, 2013 Share Posted November 29, 2013 Change them both they are cheap! Quote Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-219047 Share on other sites More sharing options...
pmolitor Posted November 30, 2013 Share Posted November 30, 2013 I bought mine at O'Reilly auto parts for $14. Quote Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-219122 Share on other sites More sharing options...
DCR Posted November 30, 2013 Author Share Posted November 30, 2013 Thanks for all of the help. As soon as I get a chance I will get both parts and rewire the system and see what happens. I emailed the same photos to a well known Mack dealer parts department and they said they have never seen the switches and had no idea what they were. I asked about the wiring since it was slightly different from the B model diagram on this site and this person suggested I buy a $1,600 wire harness to be sure everything is wired correctly. Since the truck was a road tractor and converted to a dump there have been several changes from the original truck and this would correct everything or so he thinks. Again, thanks for all of the help. I'll let you know the outcome when I finish this project Quote Denny330-550-6020A "Mack Pack" Charter Member Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-219145 Share on other sites More sharing options...
Maddog13407 Posted November 30, 2013 Share Posted November 30, 2013 sounds like someone doesn't know shit about trucks period. those switches are not Mack specific, they were on every truck around from the 40's to the 80's and most R models used the same brake light switch but it was plumbed into the treadle valve or behind the dash. the wiring looks fine to me. no need for a 1600 wiring harness. most B models are simple enough to trace the wires yourself and see what is original and what isn't. wires get broke and a new one added and disconnects, simple. a 1600 harness may fix the problem that's up to you. Quote Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-219152 Share on other sites More sharing options...
DCR Posted November 30, 2013 Author Share Posted November 30, 2013 I do not need a $1,600 harness. I have already changed a lot of wiring behind the dash and it does not need replaced with a new harness. I am far from an electrical expert and like the challenge of tracing wires and repair and replace. I will run new wires to the junction block and out of the junction block to the switch and to the lights. Will also replace the lights when doing this. The low pressure buzzer does not work so I will rebuild it when I replace the switch. Quote Denny330-550-6020A "Mack Pack" Charter Member Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-219163 Share on other sites More sharing options...
Mike Posted November 30, 2013 Share Posted November 30, 2013 Denny the answers here are the best answers. The dealers today don't want to fool with this stuff. If it is not on the computer in front of them then they can't help you. Most of the older guys are gone in retirement and took that knowledge with them. mike 1 Quote Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-219164 Share on other sites More sharing options...
High Binder Posted November 30, 2013 Share Posted November 30, 2013 DCR, You got a typical dealership response. Sell you something you don't need. I agree with Maddog13407 and I think I would find another source for my parts. Quote Link to comment https://www.bigmacktrucks.com/topic/33653-what-are-these/#findComment-219166 Share on other sites More sharing options...
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