I have been looking to purchase a new wiring kit for my 41 plymouth coupe build . From what i have been reading it is a good idea to put most of the circuits on a relay (like most new veichiles ) . I can not find a wiring kit that comes with enough relay's to power all the differnt circuit's . 3 or 4 relay's is the most i have seen in any kit . For the money you would think that these kits would be a little more updated . I ripped out the fuse box from an 98 jimmy that i scraped and in the process of figuring out all the wires for it. Hopefully i can utilize it with the relays.
Try Kwik Wire - good kits & will furnish what U need. Kwik Wire N4936 Hwy V Fond Du Lac , WI 54937 Phone: 920-921-2637
I put a horn relay in my 57 suburban when I rewired it. I couldn't find any other uses for relays. But I don't have all the modern conveniences, either....no electric fans, fuel pumps, water pumps, window motors, air bag compressors, killer stereos, etc. Just the normal old things like lights, ignition, etc.
I think i need quite a few relay's . Horn,low beam, high beam,fuel pump,electric fan. I shaved the handles and install remote door popper's ,and will be putting in power windows . and a heater . I like the looks of the Americian Auto Wire but it's over 500 plus tax up here .I have been looking on the forums of lots of different wiring diagrams and what other's have done ,but there is no real mention of people adding relay's to there kits . Since the fuse box and relays will be close together (under dash in my case ) ,I will try this fuse box i have and buy some rolls of coloured wire . I started laying it all out on a piece of plywood as i read in one of the posts
Then go get a late model fuse box and wire it like a Late model is an option. The mini Bosch relays can be purchased with the gang able holders and connectors. I got them from "terminal supply" These make a real compact and tidy relay center. Did a swap and needed Low fan, high fan, AC, power train, ignition, fuel pump, and starter relay along with 5 additional behind the glove box door. Fit nice in practically no room and super easy to get to after you empty the glove box.
Have you considered the lack of relays in wiring harnesses may be because the relays are not necessary. There are good and better wiring kits, but most of the manufacturers, I would say, have a very good understanding of an automotive electrical system and would use a relay if necessary. You definitely don't need a relay for high and low beam headlights. Assumming relays go under the dash close to the fuse box is not necessarily true either. There are a lot of books available regarding wiring a hot rod. I would suggest picking one up before you get to far along in this project.
I have very well considered why i need a relay for anything .I am sure that the harnesses being offered are good enough for what i am doing . But just from doing several hours of reading that a relay on a curcuit is a good idea because it will save whatever you are hooking up to last longer , electric fan ,fuel pump ,etc . Do you ever wonder why thy don't put more relay's in there harness, I mean all the new cars have lots of them installed . Just trying to figure out what's best . A new harness is done and ready to install ,or make my own and have it updated like a newer car ? I have the front headlights ,low and high beam floor switch ,light switch and relays working ,but it took awhile to get it done ,and that's just on the bench !
The relay helps the switch not the devise. The traditional stuff and switched are built to take the amps if they are in good shape. The late model crap uses a itty bitty switch to a bcm that has an even smaller micro switch to trigger the relay. That's why the late models have relays for every damn thing, there's no real switches on a late model.
late models have everything run by the computer, the switches are just sensors. Older cars work fine without a bunch of relays, because the switches are designed to handle the current. I suggest you use a relay for the electric fan, but you can probably get away without relays for most of the other things. Most electric fuel pumps draw less than 10 amps, and most power window switches are designed to work with power window motors.
Maybe I'm wrong but I'm pretty sure you only need relays for things that pull lots of amps. Electric fans for instance can't just be hard wired into a auto zone switch. My mechanic friend described them as using a low current to control something that uses lots of current.
American Autowire is a great wiring kit,,the Highway 22 kit should do everything you need and far far less that the 500 bucks you are talking about.HRP $390.15 buy it now http://www.ebay.com/itm/Highway-22-...m-American-Autowire-Part-500695-/160862240841
Think of a relay as a remotely controlled switch. Power goes to the relay and is switched on by a much smaller wire from a switch somewhere else. The relay needs positive and negative to switch on, so either can be controlled by a switch or sensor. Sensors normally screw into something and pass ground thru them when activated. Does that make sense? Some relays have two output connectors. One type switches from one to the other, WHEN SWITCH IS ON. A crossover relay switches from one to the other when a momentary switch activates it, and stays on that pole til switch is activated again. (Like the grounding switch in a late model column for low/high beams) That's how they do that! Sparky
Relays are designed to take load off of switches for items rated at higher current demand. It keep you from burning up contacts on headlight switches, fan switches, etc. If you use relays, make sure you size them appropriately else you will just be burning up relays instead of switches.......... Relays can be added for any component, at any time.......you just have to decide where to mount them. And the kit HRP is recommending comes with several relays.........
Listen to these guys. Don't need relays for headlights, (unless using Halogens, or higher amp bulbs) Don't need them for a fuel pump, unless wiring them with an oil pressure safety. Don't need them for power windows, heater. But it's easy to add them into a harness, in any case. You can buy Bosch relays and a molded pre-wired plug, even brackets for them from most parts stores.
Thanks for all the feedback . I was looking at the AAW Highway 22 , it looks nice and i like that the connections are all attached so you just have to run the wire back to the fusebox and connect .It was my first choice . I tend to over research things before i do them and reading about relays convinced me to use them in my harness. I'm glad that i don't realy need them and will be ordering the Highway 22 .Unfortunately 500 was the cheapest i have found .I could order from e-bay but the exchange on Can dollar ,shipping and duties will be more than that ,and if there's a problem with it ! I'll get from the local rod shop .Thanks everyone for all the input .
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