Hey everyonne. It has been a few months since I have had the time to check out the Place. I have a few trucks that are needing some emergency lights(FD & S&R) and I have been asked to do the installs on them. I could get in there with my meters and try to find an unswitched 12vdc pwr source in one of the fuse blocks/pwr panels if one exists, but I thought I would ask here before using up some time searching on the truck. I ran a few searches on the Place, but came up with nothing. I despise scotchloks(sp?), so that is not an option. I have considered installing some terminal strips in the trucks, but I hate to deplete my stock too much if there is a pwr source I can access fairly easily. I ordered my Helms manuals a while back, but haven't as yet received them. I know I can go to the terminals in the red (+) box under the hood, but if there is a source in the panels in the cab, I would prefer not to go there, as I won't always be available to troubleshoot problems and I want to try and make the circuits as simple as possible for the other truck owners. I have several LED pods, flashers, and sirens to install on my only night off from work this week, so I would appreciate any help you guys can give me.
TIA
ICE

try www.gmupfitter.com. They have electrical diagrams posted.

Jim

I've done this kind of work before and although it takes a little more time, I suggest running an 8 guage to the battery with a fuse at the battery and a terminal block at the other end, wherever that may be. If your going to wire up strobes you can count on other things being added on later and the terminal block comes in handy. It also completely isolates the truck's electrical system from the FD lights, siren, etc. I did a Furd this way and I'm glad I did because they went crazy and added radios,PA, Streamlights, and etc. That was in 1996 and the truck has not has 1 single electrical problem. If your going with LED lights and that is it, I would tap into the fusebox by the drivers door with an Add-A-Fuse tap as the LED's will not draw more than 4-5 amps max. Just my .02

sorry..I just noticed the siren.....I would go to the battery, and put in a resettable circiut breaker. It would be more obvious to the average person than to have them digging around in the dash...

the relay block under the dash on the firewall has two open distribution plugs for upfitters. One has one ignition switched accy tap, on ignition run tap and one hot always tap. I don't have a diagram handy it is shown in the service manual set. There should be a matching plug available from GM. It is used for upfitters for radio install, flashing lights etc. Hook a meter to the upper left open 6 pin recepticle to check for power. It also has a ground. All the power are fused the hot always is a believe a 20A fuse the others are 10 Amp. It is just to the left of the plug where the trailer brake harness is plugged in.

Pull the top and bottom cover off the fuse block under the hood. You can hook directly to the positive and negitive lug there. This goes direct to the battery so be sure to fuse what ever you are hooking up. To get the outer/bottom cover off you will need to take the 4 bolts out of the corner brace and remove it. This is the best source for aux power IMO.

Greg

the relay block under the dash on the firewall has two open distribution plugs for upfitters. One has one ignition switched accy tap, on ignition run tap and one hot always tap. I don't have a diagram handy it is shown in the service manual set. There should be a matching plug available from GM. It is used for upfitters for radio install, flashing lights etc. Hook a meter to the upper left open 6 pin recepticle to check for power. It also has a ground. All the power are fused the hot always is a believe a 20A fuse the others are 10 Amp. It is just to the left of the plug where the trailer brake harness is plugged in.
I've got some extra trailer brake harnesses and think u could cut off the tabs and slide them in the other positions, I'll try it on the next upgrade.

Pull the top and bottom cover off the fuse block under the hood. You can hook directly to the positive and negitive lug there...
Here is picture of what Greg is referring to.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

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Stud-2 Accessory Power (http://community.webshots.com/photo/77018086/78006348ldgpAd)<o:p></o:p>

There is an un-switched, 30 amp fused, “Stud-2” accessory circuit available under the fuse box cover (I used it to power my Lift Pump circuit). You have to remove the fender brace to get the lower cover off.

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Bill and Greg, that is where I picked up power in my own truck, I was hoping to find something under the dash for these guys though. I ended up using the #2 stud on theirs as well(Not to worry, Greg, everything gets fused.). I just had to leave a few more things disassembled until they showed up to pick them up so I could show them where power was coming from. Tim, that sounds like a good idea. Let me know what you find please. I may try to hunt up a harness and try that myself. Thanks for the input guys.