Help 70 Owners...I'm trying to fix some electrical stuff on a 70 Charger

[Nacho-RT74]

would wish to know:

-exact location of hideaways relay and how is mounted.
-How does look and same as above about horn relay.
-same than above about ignition key in buzzer.

On 3rd gens horn relay and key in buzzer are one same device, but does look 70s are different devices. 

[rick@laysons]

The headlight door motor relay is located up under the dash right next to the head light switch itself. The box part of the relay is attached to a bracket that screws into the dash frame.

I believe the horn relay is located on the passenger side inner fender close to where the horns are bolted on. It is a small box much like the head light motor relay, about 1" x 1 1/2" in size.

I'm not sure exactly where the key-in buzzer is located, I'll let somebody else chime in on that one.

[Nacho-RT74]

ok, 3rd gens and E bodies horn relays are located inside pasenger cab. No relays on engine bay, I have seen relays on engine bay frequently on 2nd gens but I was thinking they were aftermarket for some reason.

Aftermarket relays I know are driven by Positive signal, for a while our Horns AND Relays are driven by negative on column switch, unless I'm missing something on 2nd gens should it be the same

[b5blue]

The key in buzzer is between the radio and fuse block and mounted (topside) to the bottom of the steel dash frame, you may have to pull the glove box liner to find it if it is an a/c car. The horn relay is mounted the same way but just to the left of the steering column (next to the headlight door relay).Hope this helps you Nacho!

[Nacho-RT74]

yeah definitelly!!! that confirms me the horns relay engine bay mounted ARE NOT STOCK!!!!

is an A/C car dealer added ( thats why is R/T 4 speed with A/C )

I'm trying to fix this 70 R/T. Does have several gremlins and burnt wires and terminals down the dash. Engine bay plugs look fine really, at least from exterior

[b5blue]

Hey Nacho I'll help you if I can, my 70 had the dash in the trunk when I bought it(13 years ago). I just got everything working the first of this year so I remember allot still. My car had a positive cable ground out on the exhaust pipe when it had the battery in the trunk (when it was a drag only car) so it had many problems (that's why I got it). If you are trying to test the headlight door motor, leave it attached to the doors or you can mess up the motor. Keep in mind that the headlight and wiper switch have circuit breakers inside them and they can make things go off (from the heat of too much draw of current) and come back on (when the breaker cools down). Several wires are connected inside the harness together and that can drive you nuts. A factory manual for that car is money well spent for the electrical diagrams alone.     

[Nacho-RT74]

owner does have the FSM. Already fixed the hideaways doors with a bosch 5 prongs relay, but wish to get an OEM unit, no matter year ( not the repro one ), just to keep using same stock plugs

will see what I find... thanks God I'm not too bad with wiring and have some patiente.

will keep you in mind to ask about

[b5blue]

yup I bought a NOS relay off EBAY and it was no good so I used one from radio shack and made an adapter. It looks like an octopus but it works fine. I'm going to try the repro from Charger Specialty the next time I "stick my head up my dash".

[Nacho-RT74]

that one looks nice juts that plugs are diff, and I don't want to cut the eyelet terminal on car harness to fit on "signal in" input, what is a regular spade prong on repro piece.

another detail is that the outputs prongs are side by side an plug could it be inverted, making change the open/close function when headlights are on. Nothing to get mad really, but if can it be good plugged once will be better.

[b5blue]

Yes! And some later model ones have the feed (for the bolt on breaker ) going out the "other side" from the 70 ones.Those are#3513487. You could use the new adapter with blades attached to it and not "chop and splice" just plug in to harness.

[Nacho-RT74]

interesting, never heard about those.

finally removed the cluster and found some "badies"... ammeter stud are apparently loosen internally from gauge, that would explain sometimes worked some times not, and poor charge WHEN working. Will try to fix, and if not, found a NOS I think A body ammeter on a dealer, that if not fit on cluster could remove internals and fit the Charger gauge face, since are same scale rate ( 40 ) and I guess same width on studs.

Found also some wires splices. Apparently gas gauge got some problem and found wire was the problem so somebody in the past run a direct wire up to trunk.

Found a wire running from headlight dimmer switch to one of the headlight motor wires... maybe that was teh way they found to make them work

Found red wire on ign switch harness bypassed from plug because burnt

Found alternator wire location on bulkhead burnt and a direct wire throught ( tipical )

Found couple splices more around. I think one of them is hazzards/brakes related.

Found blue wire that feeds engine some melted on pass cab side close to bulkhead

Another question... found time delay flasher however NOT COURTESY LIGHT on column... are console courtesy lights time delay flasher controled too ?

Found cluster dimer switch bypassed. will check further on that and will try to fix the dimmer

Also will rebuild the engine harness.

haven't checked yet the fuse block, but I thing should it be some bad mainly because the splice I see what I think is brakes/hazzards related.

[b5blue]

You have your work cut out for you Nacho, is the ground strap on the gas gauge sending unit to the fuel line? There is a connector under the driver side kick panel that feeds the rear lights and gas gauge, that is prone to corrode also. Sounds like maybe the alt stud in the back of alt got grounded and started to fry things, maybe ign switch is going bad and resistance is melting red wire on column?Dimmer switch jumper is a bad sign of not knowing what to do! Remember brake lights go up column to turn signal switch, good idea to replace if old any way. You would be half way in to ign. switch then, pull top steering bearing case and you can get to ign. switch. Good luck glad you have a FSM! Neal

[Nacho-RT74]

Dissasembled ammeter from housing. Studs were loosen internally, same than the stud nuts externally. Internal cardboard isolator was burnt and unexistant on one of the studs sides so THIS CAR WAS READY FOR A SHORT THERE with housing!!! so removed studs ( they are/were pressed in ), will clean, aply tin and weld with torch to keep clean and welded the contact. Then new isolator and tight nut to guarantee a good contact between stud and internal plate on ammeter if gets heat and able to melt a little bit the tin. Tin will guarantee not rust and dust there.

WAS ABLE TO FIX THE DIMMER!!! is a little bit primitive fix, not a rebuilt propperlly, but will work fine. Was corroed down the plate where ends the rheostat spring so not contact between parts. Removed a little bit the plate, spring came out a little bit and fit one turn of the spring out of the plate making contact with plate externally and not down the plate.Then fit back the plate with epoxy to keep it on place with ceramic wheel. Also was some corroed/sulfated on the spinning wheel contact...

My thought about the melted red wire on ign switch plug is because the load added by A/C blower. Thats a very tipical simpthom of excesive load on that wire what feeds EVERYTHING on car ( but the lights ), and A/C blower is the BIGGER consumption device on stock parts. On my car I fit 6 relays around, 2 for headlights one for every A/C speed ( 3 speeds ), plus the heater speed what is diff than the lower A/C blower speed. No more heating there now, not even on ammeter since I have an alt able to feed everything keeping the batt out of the game, then the ammeter.

will check column switch. Fortunatelly I'm some good on that. but I think fail is not on turning switch when I saw that splice.

I don't think gas stuff is ground related since IS working, simply is not hooked to the original wire. Last "tech" run a wire from cluster plug directly to trunk. I found on back of kick panel the plug and wire around is some naked. Wire cover looks some accidentally cut, so the probable fail was allways getting full reading because accidental body ground.

[b5blue]

Very good! I always worry about fuel gauge sending unit monkey business, any mistake and you made a bomb!(not you the "other guy")When I worked on boats I heard of many problems.The melted blue wire under the hood what did it go to? I'm starting to think you saved this car from a bad fire Nacho!! Neal

[Nacho-RT74]

talking about electrical I ALLWAYS try to get the basic working becaus if they worked from factory WHY NOT NOW... unless is some upgrade, but talking about fixing.

Was the time delay flasher JUST to ign key light on 70s OR also to console courtesy lights ? I found the time delay flasher mounted from factory, still down the original cloth tape, BUT this car doesn't have ign key light... unless badly removed.

[b5blue]

I don't know that one, I will be pulling my column apart soon and finding out. Is the flasher round? I know there is a optional "headlight delay" relay, but it is kind of square. Just where is it along the dash? If it is by the emergency brake it could be one of those. The console side lights on mine worked with the dome light. Did you get the dimmer thumb wheel to turn on the dome light when it is moved all the way past bright?

[Nacho-RT74]

cilindrical... located close to emergency flasher but hanging on underdash harness not attached with bracket

headlight delay relay is a very diff stuff, this is a courtesy light time delay, used on 3rd gens to ign key courtesly light

DIMMER...yes but I checked out of the dash ( checking for continuity ) on every thumbwheel function from end to end, INCLUDING dome light turn on at the very end of thumbwheel. Working fine.

[b5blue]

Got ya, gold in color I think? I'll see tonight what I can find and let you know! Neal

[Nacho-RT74]

not gold in color.



not with the mopar decal, but you got the prongs distribution and proportions... is about 1.5" height

[b5blue]

So far only time delay I've found is to A/C. I will look in daylight today(and new flashlight)My car is easy to check no glove box A/C console carpet kick panels ect. just seats and dash. Neal

[Nacho-RT74]

got everything working ( but the car is not starting yet lol... poor spark power, have to check the reason since I'm fixing/rebuilding also the engine harness ) but FOUND a black wire traced white with female spade terminal what I didn't find where to plug... dunno remmeber that wire when I unplugged everything. Is around wiper switch area.

Found wiper switch have 2 prongs out of the main plug, one of them is of course washer, already hooked. The other one is simply without wire. I thought it could be that the destiny of that wire, but diagrams doesn't ilustrate any wire arriving there, just a resistor cable. Found the wiper switch have a resistor ballast, but is not arriving JUST RIGHT at the prong, is riveted at a side of this prong on switch and then arriving to the correct prong ilustrated on diagram..

Otherwise I remember wiper switches on 3rd gens have also an unhooked prong... maybe for an ground reinforcement if needed ?

still thinking on the time delay destination... does look IS NOT plugged anywhere beside the door jam ground and constant positive source. the plug what supposelly should feed the ign key courtesy light is just hanging around, and not ign key courtesy light on column. MAYBE REMOVED in the past ?

I don't think factory would install that flasher without the light on column.

No brakes light yet, but yes dome and hazzards. weird since checking diagram, everything is on same net. Maybe damaged switch at pedal bracket or damaged steering turning switch on column... still have to check that.

[b5blue]

Hello Nacho! I haven't gotten back in to my harness yet, I do know that the wiper harness in the dash is the same for 2 or 3 speed, BROWN with white tracer is for 3 speed (resistance cable) maybe looks black. Black with tracer feeds horn relay over buy headlight door relay. Think (not sure) that column wire would feed  light for shift indicator for column shift auto. cars. Brake light problem is most likely turn signal switch broken. Can,t find delay in FSM but found one for sale on EBAY! Neal

[Nacho-RT74]

yeah definitelly steering column turning switch is gone to brakes function. does work to the rest. I think I'll be able to fix it. will try a shot.

I simply plug the wire to the prong was free and everything works perfect. Unhooked does look was missed mid speed. really does look black to me. Brown wires to the washer still looks brown.

the wire I'm talking is hanging around comes from the time delay flasher plug, not from column. Should feed the ign key courtesy light what is unexistant at this moment. Thats the weird part... flasher present noticeably from factory but not the light on column.

plugged everything and is woking CHARMING! except for couple of stuff I still have to fix. But what I was woking on: dimmer wheel, ammeter stud and engine harness ( with some more wires around ) was kinda a plug and play job.

we discover the AC was added from SOME 3RD GEN DONOR locally down here, not in USA on a dealer as we thought. I'm able to recognice a 3rd gen box and all its system, mostly sure from a 74. Control maybe was from some 68-70 coronet donor.

[Nacho-RT74]

I think it is posible... but after everything mounted and working noticed the tach is not working... was working before remove everything. Is an aftermarket piece fit on original hole. I think is a mechanical problem with the needle stuck against its own lense ( The tach was dissasemled try to make an experiment that didn't work ). Anyway the question is if is posible remove the tach keeping the cluster in place. Does look there is room for it, but it was very late to try to remove it.

[b5blue]

Hi Nacho sounds like you are gaining ground, I have a 70 charger factory air assembly I,m not going to use if your guy is interested, it has never been repaired so I,m sure it needs a complete overhaul. Shipping would be a bitch tho.If your side A/C vent tube isn't in the way the tack should be worth a try, the speedo is the tuff one because of the brake bracing bracket, depends on how they mounted it.