Jump to content

Recommended Posts

I have a 65 B42 and as I was looking under the dash I see several factory wires are snipped off. Upon tracing two wires they end up at a black box or relay attached under the dash just beyond the steering column. I tested the wires and see that two are live. After putting ground to the live wires the box or relay starts buzzing with or without the key on. I have no idea what the box is, it could either be the horn relay or an air brake buzzer although there are no air lines to it. Could it be that the horn is stuck on?

The horn does not work upon pushing the button.

The other wires come from the heater motor and they lead nowhere.

I closed them off with tape as they were sparking everywhere. I could not find any fuses, but I am told there are breakers on this year and model.

Anyone know what this black relay or box is?

Link to post
Share on other sites
I have a 65 B42 and as I was looking under the dash I see several factory wires are snipped off. Upon tracing two wires they end up at a black box or relay attached under the dash just beyond the steering column. I tested the wires and see that two are live. After putting ground to the live wires the box or relay starts buzzing with or without the key on. I have no idea what the box is, it could either be the horn relay or an air brake buzzer although there are no air lines to it. Could it be that the horn is stuck on?

The horn does not work upon pushing the button.

The other wires come from the heater motor and they lead nowhere.

I closed them off with tape as they were sparking everywhere. I could not find any fuses, but I am told there are breakers on this year and model.

Anyone know what this black relay or box is?

May be the low air buzzer.

glenn akers

Link to post
Share on other sites
I have a 65 B42 and as I was looking under the dash I see several factory wires are snipped off. Upon tracing two wires they end up at a black box or relay attached under the dash just beyond the steering column. I tested the wires and see that two are live. After putting ground to the live wires the box or relay starts buzzing with or without the key on. I have no idea what the box is, it could either be the horn relay or an air brake buzzer although there are no air lines to it. Could it be that the horn is stuck on?

The horn does not work upon pushing the button.

The other wires come from the heater motor and they lead nowhere.

I closed them off with tape as they were sparking everywhere. I could not find any fuses, but I am told there are breakers on this year and model.

Anyone know what this black relay or box is?

Your best path of progression with an old truck's wiring is a good "point to point" electrical diagram, and a multimeter. Many vehicles have burnt severely using "plug and chug" troubleshooting. Guessing to which wire goes where can be, and usually is costly in the end. You are working with cloth covered, plastic jacketed wiring, that is 40 plus years old and brittle. It breaks easily and disturbing it's natural "lay" can be very detrimental while tracing for problems. With an electrical print, you do not have to disturb anything, just probe point A, & B, for continuity and/or voltage and current flow.

An older service manual will have electrical diagrams, theory of operation, and normal indications listed. The website www.oldmacksrus.com is a very good place to start.

No one here can fix your trucks, only give suggestions obtained through experience to the questions you ask. The actual repair takes homework and labor on your part. Obtaining an answer from a website such as this is not always going to be accurate, as we are not actually looking at the problem(s) inquired about. I'd hate for you to go off on a tangent to accomplish someones suggestion, and it be incorrect, causing you future grief.

I gather from your previous posts, and questions, that you have little experience with trucks from the standpoint of repair/maintenance. Nothing wrong with that as we all have to start somewhere. I, along with others, will help most anyway we can with a project but I don't personally like to feel the person asking the questions is not trying on their own for accomplishment. There is no negative reference in that last comment. If someone is trying, I will do my best to help them.

Now I think I'll have a quart of beer, and a large bowl of momma's potato salad, along with a few boiled eggs, so I can entertain the guys at work tomorrow.

Rob

Dog.jpg.487f03da076af0150d2376dbd16843ed.jpgPlodding along with no job nor practical application for my existence, but still trying to fix what's broke.

 

 

Link to post
Share on other sites
Your best path of progression with an old truck's wiring is a good "point to point" electrical diagram, and a multimeter. Many vehicles have burnt severely using "plug and chug" troubleshooting. Guessing to which wire goes where can be, and usually is costly in the end. You are working with cloth covered, plastic jacketed wiring, that is 40 plus years old and brittle. It breaks easily and disturbing it's natural "lay" can be very detrimental while tracing for problems. With an electrical print, you do not have to disturb anything, just probe point A, & B, for continuity and/or voltage and current flow.

An older service manual will have electrical diagrams, theory of operation, and normal indications listed. The website www.oldmacksrus.com is a very good place to start.

No one here can fix your trucks, only give suggestions obtained through experience to the questions you ask. The actual repair takes homework and labor on your part. Obtaining an answer from a website such as this is not always going to be accurate, as we are not actually looking at the problem(s) inquired about. I'd hate for you to go off on a tangent to accomplish someones suggestion, and it be incorrect, causing you future grief.

I gather from your previous posts, and questions, that you have little experience with trucks from the standpoint of repair/maintenance. Nothing wrong with that as we all have to start somewhere. I, along with others, will help most anyway we can with a project but I don't personally like to feel the person asking the questions is not trying on their own for accomplishment. There is no negative reference in that last comment. If someone is trying, I will do my best to help them.

Now I think I'll have a quart of beer, and a large bowl of momma's potato salad, along with a few boiled eggs, so I can entertain the guys at work tomorrow.

Rob

Thanks for the input and advice thus far on this issue and the others I sought, it is very much appreciated. You are correct that I don't know much about 50 year old obsolete trucks, however I have a very good knowledge of mechanics, diesel and gas engines of numerous other machines, trucks and cars. I currently do not have a service manual for either B model I currently own as I just started working on them, I have never serviced any of the components on one of these before this year, nor have I any idea about its design or its more complicated functions such as wiring or the mack engine. I am on this site to learn and to seek out advice from people who are more familiar with this particular model of mack, assuming that is what this forum site is about. I can only assume that most people who use this site are here to help and having said that I am trying to take advantage of years of their valuable experience working with and on old mack trucks. I do all my own work and when I put forth a question I don't want you or others to assume I know nothing about trucks or mechanics and am seeking answers for everything I endevour then hold the adviser responsible for the repair. I also have never said nor would I ever blame anyone for wrong advice or something that went aray as a result. Advice is free everything else costs.

Again, I am not familiar with the B model macks, but I am learning fast with help along the way from both hands on and from whatever information I have researched, requested or some kind person has offered.

I do appreciate all the input that anyone has added on my particular post and I try the suggestions, if I think it is worthy. I will also reply to others who post questions if I can help and I don't expect everyone to heed my advice as gospel, after all that is why this site and others like it exist, give and take. All I can ask is that if someone is willing to help me on something specific I ask and they might think it would help, than that would be great. If they don't wish to help me or anyone else for whatever reason than that is ok too. I am new on this site and am new to the old mack truck game as well. But as you say, we have to start somewhere.

Link to post
Share on other sites
Thanks for the input and advice thus far on this issue and the others I sought, it is very much appreciated. You are correct that I don't know much about 50 year old obsolete trucks, however I have a very good knowledge of mechanics, diesel and gas engines of numerous other machines, trucks and cars. I currently do not have a service manual for either B model I currently own as I just started working on them, I have never serviced any of the components on one of these before this year, nor have I any idea about its design or its more complicated functions such as wiring or the mack engine. I am on this site to learn and to seek out advice from people who are more familiar with this particular model of mack, assuming that is what this forum site is about. I can only assume that most people who use this site are here to help and having said that I am trying to take advantage of years of their valuable experience working with and on old mack trucks. I do all my own work and when I put forth a question I don't want you or others to assume I know nothing about trucks or mechanics and am seeking answers for everything I endevour then hold the adviser responsible for the repair. I also have never said nor would I ever blame anyone for wrong advice or something that went aray as a result. Advice is free everything else costs.

Again, I am not familiar with the B model macks, but I am learning fast with help along the way from both hands on and from whatever information I have researched, requested or some kind person has offered.

I do appreciate all the input that anyone has added on my particular post and I try the suggestions, if I think it is worthy. I will also reply to others who post questions if I can help and I don't expect everyone to heed my advice as gospel, after all that is why this site and others like it exist, give and take. All I can ask is that if someone is willing to help me on something specific I ask and they might think it would help, than that would be great. If they don't wish to help me or anyone else for whatever reason than that is ok too. I am new on this site and am new to the old mack truck game as well. But as you say, we have to start somewhere.

Hmmmm, obviously struck a nerve here. Sorry 'bout that don'tcha know. Never meant to offend.

I'll hereby withdraw my interest and cause you no further dispair.

Good luck, and enjoy our hobby.

Rob

Dog.jpg.487f03da076af0150d2376dbd16843ed.jpgPlodding along with no job nor practical application for my existence, but still trying to fix what's broke.

 

 

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...