I want to pass along a modification I did to my truck last August. I had the dash out and was thinking about adding front and rear dash cameras. I already had one of those Motorola hands free units that you put on your visor but wanted to power the hands free and cameras without wires hanging all over. I got to thinking about putting in permanent power for these USB devices. DC-DC converters are really cheap these days so I decided I might as well install one in place of my dash gauge regulator. The maximum voltage to put on a USB port is about 5.2V and the dash gauges use 5.4VDC. Unfortunently not close enough to use just one DC-DC converter, but they are pretty cheap.
I ordered a four pack of 5A DC-DC Adjustable Buck Converters, two for the truck and two for my next in line project for about $15. I had a small metal project box to put two of these in, and added two 3/32" holes to allow me to adjust these after installation. While the dash was out, I took out the headliner board. I mounted the box with the converters up near the dash cover with the adjustment holes pointing down. I had pre adjusted the voltages to 5.2V and 5.4V. I ran a power lead from the ignition/accessory wire to the converter box and ran a wire from the 5.4V converter to the dash, in place of the old mechanical voltage regulator. I ran three more wires (long USB cables) from the 5.2V up to the roof area, with two near the rearview mirror and one by the rear center area by the interior light. I buttoned up the headliner and dash, hooked up the cameras and handsfree and tried it out. When I turned on the truck the cameras come on and the handsfree announced it was connected to my phone. I checked the calibration of the dash gauges and they were spot-on.
I have been driving the truck with this conversion since August and not encountered any problems. The dash gauges were alright before but after 50 years, replacing the voltage regulator might be a good idea. It is also nice to not have USB cables hanging around the windows, plus there is no stock place to plug them all in. This has worked out for me. I am sure others have the multiple USB problem as well so might benefit from my solution. If there is any interest, I can diagram the wiring for the DC-DC converters.
DC-DC converters for your truck
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JoshT
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Re: DC-DC converters for your truck
That sounds very interesting. I don't need a new instrument cluster voltage regulator as mine was recently replaced and I intend to convert to Dakota Digital eventually, but USB power is something I don't think I could have enough of.
I've seriously considered running a dash cam full time due to the number of people that like to slam on brakes in front of me and/or don't have brake lights. That, a handsfree device without running wires all over the place, a few ports to charge usb devices without needing a lighter adapter.
If you don't mind sharing more info, I'm sure it would be appreciated.
I've seriously considered running a dash cam full time due to the number of people that like to slam on brakes in front of me and/or don't have brake lights. That, a handsfree device without running wires all over the place, a few ports to charge usb devices without needing a lighter adapter.
If you don't mind sharing more info, I'm sure it would be appreciated.
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DisneysPatB
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Re: DC-DC converters for your truck
zgerbic wrote:I want to pass along a modification I did to my truck last August. I had the dash out and was thinking about adding front and rear dash cameras. I already had one of those Motorola hands free units that you put on your visor but wanted to power the hands free and cameras without wires hanging all over. I got to thinking about putting in permanent power for these USB devices. DC-DC converters are really cheap these days so I decided I might as well install one in place of my dash gauge regulator. The maximum voltage to put on a USB port is about 5.2V and the dash gauges use 5.4VDC. Unfortunently not close enough to use just one DC-DC converter, but they are pretty cheap.
I ordered a four pack of 5A DC-DC Adjustable Buck Converters, two for the truck and two for my next in line project for about $15. I had a small metal project box to put two of these in, and added two 3/32" holes to allow me to adjust these after installation. While the dash was out, I took out the headliner board. I mounted the box with the converters up near the dash cover with the adjustment holes pointing down. I had pre adjusted the voltages to 5.2V and 5.4V. I ran a power lead from the ignition/accessory wire to the converter box and ran a wire from the 5.4V converter to the dash, in place of the old mechanical voltage regulator. I ran three more wires (long USB cables) from the 5.2V up to the roof area, with two near the rearview mirror and one by the rear center area by the interior light. I buttoned up the headliner and dash, hooked up the cameras and handsfree and tried it out. When I turned on the truck the cameras come on and the handsfree announced it was connected to my phone. I checked the calibration of the dash gauges and they were spot-on.
I have been driving the truck with this conversion since August and not encountered any problems. The dash gauges were alright before but after 50 years, replacing the voltage regulator might be a good idea. It is also nice to not have USB cables hanging around the windows, plus there is no stock place to plug them all in. This has worked out for me. I am sure others have the multiple USB problem as well so might benefit from my solution. If there is any interest, I can diagram the wiring for the DC-DC converters.
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1999 Dodge Durango SLT 4 x 4 5.9 Magnum -not running.
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zgerbic
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Re: DC-DC converters for your truck
I did the conversion back in August so don't have original pictures. Was not thinking about passing this conversion along at the time.
Make sure you get a 5A converter to drive the USB devices. If you want to power the dash and some USB ports, then get two or more converters. I used 5A DC-DC Adjustable Buck Converter 4~38v to 1.25-36v Step Down Power Supply High Efficiency Voltage Regulator Modules. There are some four-packs for about $10 to $15. If you just want one converter then DZS Elec 1pcs DC-DC 5A 4-38V to 1.25-36V Step-down Regulator Module is about $7 and has a heatsink that would help with heat dissipation.
The converter for the dash gauges must be an adjustable one as it needs to be set to 5.4V to get the gauges reading exactly right.
If you are just powering USB devices then you could get by with a fixed 5.1V to 5.2V converter. I would not go below 5.1V since you will have some long/small gauge wires going to the USB devices and will lose a tenth of a volt or so in the long wires.
You will need a small metal box (similar to BUD Industries CU-2100-B Aluminum Electronics Minibox for one converter, bigger for two) to protect the converter and allow easy mounting. I mounted my converters next to each other on plastic standoffs (to prevent shorting the bottom of the PCBs against the metal box. I drilled a hole in one end to run the wires through (power in and all the USB cables) and used a rubber grommet to protect the wires.
Most USB devices use micro-C cables. The cameras I used had mini-B so I used two of these cables for the cameras and a micro-C for my hands-free. You will need to determine where the DC to DC converter box will be mounted so you can determine how long the cables will need to be. I think I used 7' for the wires going to the rear view mirror area and a 10' to the interior light area. Once the headliner is removed it becomes easy to run the USB cables.
You might consider adding a charging cable for you cell phone as well (run to the ashtray, glovebox or wherever you sit your phone). Finding the correct power wires inside the phone charging cable might be a little harder but can be done in the same way as the other USB cables, described below.
You need to make sure the polarity is correct and you cannot trust the wire colors in the USB cables. I would cut off the USB A ends with a couple of inches of wire left so I could strip back the covering/shielding to get to the inner wires. Strip back the individual wires in the cable and connect the USB A end into a USB charger. There should be two wires in the cable that carry +5V and ground (-). Find the 5V wire. While this is connected to a voltmeter, probe the other wires to find any that appear to be ground, there may be two (power ground and shielding ground). If there are two, disconnect the USB A connection and ohm out the two ground wires to the metal shield on the USB A connection. Use the ground that is not the shield for your ground (-) connection.
After you have figured out the colors for each cables + and - connections find those wires in the long cables. Connect all the + connections together along with a 18 gauge wire and that will be +5V connection to the converter. Connect all the ground connections together along with an 18 gauge wire and that will go to the -V connection on the converter. Make sure the wires are well insulated.
Run the wires through the grommet on the metal box along with two 18G or 16G wires to be used for the power in. Connect the 12V power input wires to the converter and the 5V USB wires as shown in the illustration/picture below. It is important to build the metal box with the converters and power holes on the same half of the metal box. The other half can then be attached to the firewall or bottom of dash pad metal with sheet metal screws. Doing this will allow the metal box half with the converter and wiring to be attached or removed easily. I would ground the converter power in connection to a metal point on the dash/firewall. Make sure it is positioned so you can put in the four small machine screws.
Next I would connect the +12 power in connection to a switched source of power. Could be the ignition switch or a fuse controlled by the ignition switch. The converter will draw about 2.5A maximum. You could put in an inline fuse to the ignition switch. Once the power connections are done, measure the voltage at the USB connection and adjust, if necessary, for +5.2VDC. When done you can close up the metal box and screw it together. Make double sure that the screws used in the box will not come near the converters as you don't want a short.
You can pull the USB cables that go to the headliner using a coat hanger wire or similar down the drivers A pillar post. The USB wires can be arranged to come out with enough wire to reach the front and rear facing cameras, and a handsfree device (or whatever you were going to power). That is what I did. Reinstall the headliner. This is a good time to insulate the roof if needed.
This should complete the installation of the converter to the USB cables.
If you are replacing the dash voltage regulator it can be done in a similar fashion. I put two converters in the same metal box but each can be separate. To replace the dash regulator, remove the dash and see which wires are used for the old regulator connections. You will need to find the +12V input (normally a male fast-on connector) and the control (pulsing) output (normally a female fast-on connector). Use the wiring diagram or the voltmeter to find the output that connects to the gauges. Remove the dash regulator and connect the output of the converter to the dash gauge power connection (wire that was connected to the control pin on OEM regulator). You can connect the input to the converter as suggested above or connect the converter +12V input connection to the +12V input used by the old dash regulator. Adjust the converter for 5.4VDC. When the ignition is on, the gauges should read close to the same as when the old OEM type regulator was in place.
Make sure you get a 5A converter to drive the USB devices. If you want to power the dash and some USB ports, then get two or more converters. I used 5A DC-DC Adjustable Buck Converter 4~38v to 1.25-36v Step Down Power Supply High Efficiency Voltage Regulator Modules. There are some four-packs for about $10 to $15. If you just want one converter then DZS Elec 1pcs DC-DC 5A 4-38V to 1.25-36V Step-down Regulator Module is about $7 and has a heatsink that would help with heat dissipation.
The converter for the dash gauges must be an adjustable one as it needs to be set to 5.4V to get the gauges reading exactly right.
If you are just powering USB devices then you could get by with a fixed 5.1V to 5.2V converter. I would not go below 5.1V since you will have some long/small gauge wires going to the USB devices and will lose a tenth of a volt or so in the long wires.
You will need a small metal box (similar to BUD Industries CU-2100-B Aluminum Electronics Minibox for one converter, bigger for two) to protect the converter and allow easy mounting. I mounted my converters next to each other on plastic standoffs (to prevent shorting the bottom of the PCBs against the metal box. I drilled a hole in one end to run the wires through (power in and all the USB cables) and used a rubber grommet to protect the wires.
Most USB devices use micro-C cables. The cameras I used had mini-B so I used two of these cables for the cameras and a micro-C for my hands-free. You will need to determine where the DC to DC converter box will be mounted so you can determine how long the cables will need to be. I think I used 7' for the wires going to the rear view mirror area and a 10' to the interior light area. Once the headliner is removed it becomes easy to run the USB cables.
You might consider adding a charging cable for you cell phone as well (run to the ashtray, glovebox or wherever you sit your phone). Finding the correct power wires inside the phone charging cable might be a little harder but can be done in the same way as the other USB cables, described below.
You need to make sure the polarity is correct and you cannot trust the wire colors in the USB cables. I would cut off the USB A ends with a couple of inches of wire left so I could strip back the covering/shielding to get to the inner wires. Strip back the individual wires in the cable and connect the USB A end into a USB charger. There should be two wires in the cable that carry +5V and ground (-). Find the 5V wire. While this is connected to a voltmeter, probe the other wires to find any that appear to be ground, there may be two (power ground and shielding ground). If there are two, disconnect the USB A connection and ohm out the two ground wires to the metal shield on the USB A connection. Use the ground that is not the shield for your ground (-) connection.
After you have figured out the colors for each cables + and - connections find those wires in the long cables. Connect all the + connections together along with a 18 gauge wire and that will be +5V connection to the converter. Connect all the ground connections together along with an 18 gauge wire and that will go to the -V connection on the converter. Make sure the wires are well insulated.
Run the wires through the grommet on the metal box along with two 18G or 16G wires to be used for the power in. Connect the 12V power input wires to the converter and the 5V USB wires as shown in the illustration/picture below. It is important to build the metal box with the converters and power holes on the same half of the metal box. The other half can then be attached to the firewall or bottom of dash pad metal with sheet metal screws. Doing this will allow the metal box half with the converter and wiring to be attached or removed easily. I would ground the converter power in connection to a metal point on the dash/firewall. Make sure it is positioned so you can put in the four small machine screws.
Next I would connect the +12 power in connection to a switched source of power. Could be the ignition switch or a fuse controlled by the ignition switch. The converter will draw about 2.5A maximum. You could put in an inline fuse to the ignition switch. Once the power connections are done, measure the voltage at the USB connection and adjust, if necessary, for +5.2VDC. When done you can close up the metal box and screw it together. Make double sure that the screws used in the box will not come near the converters as you don't want a short.
You can pull the USB cables that go to the headliner using a coat hanger wire or similar down the drivers A pillar post. The USB wires can be arranged to come out with enough wire to reach the front and rear facing cameras, and a handsfree device (or whatever you were going to power). That is what I did. Reinstall the headliner. This is a good time to insulate the roof if needed.
This should complete the installation of the converter to the USB cables.
If you are replacing the dash voltage regulator it can be done in a similar fashion. I put two converters in the same metal box but each can be separate. To replace the dash regulator, remove the dash and see which wires are used for the old regulator connections. You will need to find the +12V input (normally a male fast-on connector) and the control (pulsing) output (normally a female fast-on connector). Use the wiring diagram or the voltmeter to find the output that connects to the gauges. Remove the dash regulator and connect the output of the converter to the dash gauge power connection (wire that was connected to the control pin on OEM regulator). You can connect the input to the converter as suggested above or connect the converter +12V input connection to the +12V input used by the old dash regulator. Adjust the converter for 5.4VDC. When the ignition is on, the gauges should read close to the same as when the old OEM type regulator was in place.
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