Power question

[sdeeter19555]

Take a look at the information at this link:

https://service.gm.com/techlineinfo/radio.html

This covers a little bit more than just wiring.

Dated 2002, just a little dated considering the electronics in these newer trucks...

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[rivardj]

Still applicable. GM vehicles have been loaded with ECUs well before 2002.

I have a fellow ham radio friend that works in the EMC department at the GM Milford Proving Ground. Up until a few years ago he used to go to Dayton with a display vehicle and a crew from GM to answer questions from hams at the Hamvention about these very topics. They used to hand out that guide in their booth. I can check with him to find out if there has been a revision to that document but I doubt there has as not much has changed that would affect the content of the document.

 

[sdeeter19555]

Not as sensitive as they are now...gm upfitters is a better read...

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[sdeeter19555]

https://www.gmupfitter.com

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[sdeeter19555]

Much better and more current source than a 14 year old document...been down this road, not wasting my breath.

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[rivardj]

Can you point out on which of the 108 pages in the upfitters guide that Radio Telephone / Mobile Radio
Installation Guidelines are specifically addressed? I must have missed the diagrams and figures that directly address the questions that were asked in the original post. I also must have missed the antenna cable routing, radio wire routing, the transceiver mounting safety precautions and suggestions on how to determine the best antenna mounting location so as not to interfere with the sensitive electronics in the vehicle.

Don't get me wrong, the upfitters guide does have a lot of good information in it, but it does not directly address radio installations. For radio installations guidelines my money is on the Radio Telephone / Mobile Radio Installation Guidelines document.

 

[SCPD]

There will be a never ending debate on grounding to the frame or directly to the battery. If you do ground to the battery, fuse your negative lead. The fuse will blow rather than melting the negative lead back and possibly doing some bad damage such as a fire if the main negative side battery wire were to come loose. If you ground to the frame, you don't have to have a fuse on the negative wire.
. A good radio chassis ground will help with RF noise. The shorter the better. You will see a lot of flat braid bonding straps in cars from the hood, trunk & exhaust systems to ground just for the purpose of RF suppression.

Mike

Your right about that, a never ending debate. I have had two different professional radio shops run both the fused + and - leads directly to the battery. Never did suffer from RF noise affecting anything including car electronics. Since two different shops did it that way, I did not question their work. In my opinion a frame ground would be better, but there were no issues the other way so did not question the direct battery. I normally do all my radio installations, mounting, running power and installing the NMO mounts and would have grounded it to the frame. The car was a pain trying to get power lines through the firewall and running the antenna lines from the roof mounted NMO mounts. I just had the radio shops do all the work to save my sanity.

 

[sdeeter19555]

Can you point out on which of the 108 pages in the upfitters guide that Radio Telephone / Mobile Radio
Installation Guidelines are specifically addressed? I must have missed the diagrams and figures that directly address the questions that were asked in the original post. I also must have missed the antenna cable routing, radio wire routing, the transceiver mounting safety precautions and suggestions on how to determine the best antenna mounting location so as not to interfere with the sensitive electronics in the vehicle.

Don't get me wrong, the upfitters guide does have a lot of good information in it, but it does not directly address radio installations. For radio installations guidelines my money is on the Radio Telephone / Mobile Radio Installation Guidelines document.

Again, your warranty...

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[sdeeter19555]

This is the reason I so infrequently post on this forum, guys who get hung on one thing and then chase you around like a cyber bully until you bow to them.

I'm going to use a 14 year old document hat tells me to cut and hack my truck's wiring when the newer GM dealer and gm guidance says not to because of the sensitivity of the electronics. I went down this road in a Dodge, and paid for a new dash cluster because my CB was tied into the cigarette lighter wiring. I went down this road (correctly) with this Silverado because of that experience...I called the dealer about RF considerations, and when they couldn't help I called GM and went through hours with them on the phone. I also tied into the truck's electrical system in a manner recommended and approved by GM...I valued my warranty. That wasn't easy as it takes tying into a single pin on a 20 pin block with small spades. I also included the diode recommended between the ground and the relay trigger as specified to protect the wiring...

But why take advice from someone with a model truck within the same year, let alone the same decade? This will be my last post for quite some time...I've wasted enough of my time and as I tell others, it's not my truck or my warranty.

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[jim202]

There will be a never ending debate on grounding to the frame or directly to the battery. If you do ground to the battery, fuse your negative lead. The fuse will blow rather than melting the negative lead back and possibly doing some bad damage such as a fire if the main negative side battery wire were to come loose. If you ground to the frame, you don't have to have a fuse on the negative wire.
. A good radio chassis ground will help with RF noise. The shorter the better. You will see a lot of flat braid bonding straps in cars from the hood, trunk & exhaust systems to ground just for the purpose of RF suppression.

Mike

The fuse in the negative wire and going directly to the battery is a never ending thread of people that are listening to the CB and Ham radio vendors. The major radio vendors like Harris, Motorola, Tait and some others that are no longer with us, never provided anything but a short black wire to go to the frame of the vehicle.

I have been around the public safety and industrial radio field a long time. Have seen and even done a good number of installs in fire truck, dump trucks, cement mixers and all sorts of other heavy duty vehicles. Not once in all the years have I ever come across a case where the ground from the radio has melted or caused a fire in any of these vehicles around the country.

Bear in mind that the normal consumer vehicle is using an alternator in the order of any thing from 60 amps. to around 120 amps. The size depends on the vehicle and the electronics packages installed. In these heavy duty vehicles, your talking charging alternators starting about 200 amps. and going up to even 800 amps. or more. Do you think a measly number 14 or even a number 10 wire rated at 30 amps. is going survive the current these heavy duty charging circuits if there is a problem? If there was a grounding problem, there would have been issues years ago that would have shown up.

Even the dash AM / FM radios in these vehicles use the chassis ground for the negative return. Based on the number of these heavy duty vehicles on the road and the lack of information on any electrical problems and or fires, I would have to place the stories that continue to propagate through chat groups like this one into the "Old Wives Tales" heading. Plus it is helped along by the off shore vendors that just insist on providing long black wires with fuses. They tell you to go to the battery terminal with them. But do they really give a reason for doing this?

One other point I will bring out before some go crazy and exploit it. If the ground wire from the battery to the vehicle frame starts to go bad, be it a poor connection or a damaged wire, you will see problems with starting the engine by pulling heavy current with the starter motor. This then would cause your to look for service or repair it your self.

The high current flow from the battery to the starter motor is through the battery grounding wire. There should be a heavy braided cable from the frame to the engine or even a heavy ground wire. This is the heavy current carrying conductor. Not any coax cable from the antenna wire to the radio chassis and then to the vehicle frame.

The so called experts that continue to propagate the story of the reason for the fuse in the ground wire of the radio really need to explain in detail why they keep pushing their view of the story. You need to ask these people where they are getting their information from and what it is based on. Facts tell the story not folk lore.

 

[KC2GIU]

This is the reason I so infrequently post on this forum, guys who get hung on one thing and then chase you around like a cyber bully until you bow to them.

I'm going to use a 14 year old document hat tells me to cut and hack my truck's wiring when the newer GM dealer and gm guidance says not to because of the sensitivity of the electronics. I went down this road in a Dodge, and paid for a new dash cluster because my CB was tied into the cigarette lighter wiring. I went down this road (correctly) with this Silverado because of that experience...I called the dealer about RF considerations, and when they couldn't help I called GM and went through hours with them on the phone. I also tied into the truck's electrical system in a manner recommended and approved by GM...I valued my warranty. That wasn't easy as it takes tying into a single pin on a 20 pin block with small spades. I also included the diode recommended between the ground and the relay trigger as specified to protect the wiring...

But why take advice from someone with a model truck within the same year, let alone the same decade? This will be my last post for quite some time...I've wasted enough of my time and as I tell others, it's not my truck or my warranty.

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Oh my. That must have drove your crazy dealing with GM like that. Then to find out how to literally make that connection on a connector block. That is almost like using a computer power supply without a computer. A jumper needs to be used.

Hope that when you traded-in or sold the truck, the steps you had taken were easy to reverse.

 

[MBill]

I agree with Hummermike. If you use battery ground make sure wire is fused. I've seen happen
what he describes on an old Kenwood TK-705D that was grounded to the battery without a fuse.
Ground wire melted back to the radio. Fortunately no fire. The TK-705D power cables came with
fuses on both positive and ground leads, but for some reason, installer did not use fuse on the ground
side to the battery.

 

[z31jaime]

Only times I have ever seen a ground wire melt in thousands of installs and retrofits I've worked on was either an oversized positive fuse or an undersized ground wire such as a 10ga positive and a 16ga ground wire (yes I have found that)

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[KC4RAF]

You NEVER, EVER fuse the ground (negative)

wire; for any reason. You fuse the red (plus, +) wire.
Fusing the negative will only add to your headaches and pocket book later on.

 

[HummerMike]

Wow, this could go on forever. I have built over 100 Patrol vehicles with Radios, sirens, dash cams, Radar, Light bars ect., ect. Never had any problems from the way I put them together. With that, I do ground to the frame. No fuse in the ground lead. But,,,,, if I do ground to the cranking battery, it WILL have a fuse in the ground lead. Just in the rare case a main ground lead came loose I would rather have a sacrificial fuse blow rather than a melted 16~18 gauge wire going to the radio.
Just think, we won't have to worry about all this in 10 years. It will most likely be illegal to self install any aftermarket accessory on to a vehicle. If you want a particular radio, just buy the App and have it activated or installed by a govt. approved dealer.

 

[rivardj]

HummerMike is spot on regarding fusing a ground wire that is attached directly to the starter battery verses connecting the ground wire to the vehicle body / frame. I think some of the controversy comes from people not differentiating between the two types of ground connections.

At the risk of coming off as a cyber bulling stalker, I have an update regarding the Radio Telephone / Mobile Radio Installation Guidelines document I posted a link to earlier in this thread. I traded emails with my contact in the GM EMC lab at the GM Milford Proving Ground, he confirmed the document I linked to is the current version.

As an aside, when documents, and not just technical documents, are published the document is dated and sometimes given a document number. The document stands as valid until superseded by an updated document. If the information contained in the document is still current and valid the document is not altered, including changing the date. The contents of a document are not invalid just because a document was released, as in this case, fourteen years ago.

Also of note, Ford has a very similar document available at the link below:

http://www.fordemc.com/docs/download/Mobile_Radio_Guide.pdf

If you read both the Ford an GM documents you will find some of the recommendations are almost cut and paste. There are reasons for that which I will not go into here.

Here is the link to the GM document I reference in my earlier post:

https://service.gm.com/techlineinfo/radio.html

This is a section of the GM guidelines that states the reason for fusing ground wires directly connected to the vehicle battery. Hopefully this clears up some of the controversy regarding the fuse in ground wires connected directly to a vehicles battery.

"B. If connections are made directly to the battery terminals, the GM approved methods of connecting auxiliary wiring include the adapter package illustrated in Figure 2, NAPA-Belden replacement battery bolts (part # 728198), or drilling and tapping the hex end of the original battery bolts 10-32 X 3/8" deep. NOTE: It is recommended that a fuse be placed in the transceiver negative lead to prevent possible transceiver damage in the event the battery to engine-block ground lead is inadvertently disconnected."

I do not think that if the installation guidelines in either of the two documents I have provided links to are followed that there would be any warranty issues.

I would like everyone to understand that my sole purpose of not dropping this subject is to help minimize the controversy on this subject. The documents referenced contain the recommendations from the companies that design and manufacture the vehicles. There is extensive testing done at Ford, GM and their suppliers for many of the systems on the vehicles they produce, that is how they determine the guidelines. I have personally spent a good portion of the last 20 years of my career, as an employee of a major automotive supplier, at both the Ford and GM proving ground and other engineering facilities at both companies performing tests on various vehicle systems.

A pet peeve of mine is that some people, in good faith, offer advice on subjects they know little more about than the person asking for help. I know what I don't know and do not offer advice unless it is regarding a subject of which I have some standing. An old saying that I have found to be true is that bad data is worse than no data. The same goes for advice. Enough said.

 

[Awz1287]

Thanks for all the info. I have been reading through everything. I have not had a chance to work on anything yet, do to my work schedule. I was finally off today and it rained all day, I'm hoping for a better day tomorrow.

Any one know what gauge wire comes on the stock harness? If I need to add more wire I should stick with the same gauge?
What gauge should I use for the radio chassis grounding and the antenna bracket?

 

[mmckenna]

If you are asking about the sun roof circuit, it's pretty small. I'd say it was 18 gauge at most, maybe 16 gauge, but I doubt it.
If you are just going to use it to power the radio, then keep the same size, maybe go with 16ga.
Preferably, use the sun roof circuit to control a power relay only, power the radio off the battery, through the relay to give you ignition on/off with retained accessory power.

As for the radio ground, if the run is short, the 16 gauge would be fine. Antenna ground should ground through the mount.

 

[Awz1287]

I was thinking of running the power directly to the battery. I was wondering about the uniden harness that came with the radio. I am probably going to need more wire then the stock power cord, I was going to add more wire. is wire nuts, then wrapped in electrical tape, an ok method? Should I go with 16 gauge?

 

[HummerMike]

The most simple and safe way is to ground to the chassis with your black wire. Most vehicles have a group of wires going to the body ground behind the kick panel. Just put a ring lug on the black wire and take the screw out and add this wire under the screw also. For the red wire, get a small spool of #16 or #14 from your local auto parts supply. Pick up a blade type fuse holder and a 4 to 5 Amp fuse. Get some butt splice connectors, if you have now way of soldering. Cut the red wire about a foot out from the radio plug. Connect your purchased wire to the red wire with one of the butt splice connectors. Make sure you did a good job on the butt splice crimping. Run the red wire to the battery or more preferably, the red main junction block near the battery. Install the fuse holder in line with the red wire at the battery hook up. Install your fuse. You will be good to go. Also it would be good to get some small wire loom to run the red wire in to prevent from chaffing the wire. Don't use the original fuse holder with the round glass fuse. The white plastic will crumble in no time with the heat and weather.