Should I install 40A 12VDC relays?

[Arberg0]

From: larry060748  (Original Message) Sent: 11/30/2003 9:35 PM


I have a 1979 brave w/M400 chassis 360 dodge engine. I was reading on another board that on older rigs virtually all the chassis power comes through the keyswitch. Therefore one should add a pair of 40A 12VDC load reduction relays that allow operation of lights and heater blower/Air cond. on seperate circuits through the relays. I haven't had any problems with my ignition but should I do this now or wait to I have a problem. Anyone know if this is true or can describe what needs to be done. Where would I get such circuits. 


 

From: dave76Chieftain Sent: 12/1/2003 6:17 AM
Some of the fused circuits do come through the ignition switch, some don't.  Most lighting does not come via the ignition switch.  High current circuits like the lights and horn already had relays installed (something like 15 amp rating though).  On my 78 Chieftain, the heater fuse (ignition switched) drives a constant voltage relay (just like the battery relay) mounted under the dash.  Dash heater is actually powered by coach battery.  Dash heater is a Winne add on (Dodge did not supply the heater).  Try looking at some of the Dodge MH chassis wiring diagrams on the web to see what all is there and how things are hooked up.  They are simular for all years with minor differences. 

Dave
78 26' Chieftain

   

From: denison Sent: 12/1/2003 8:03 AM
None of my wiring info covers up to the 79s unfortunately, but I agree that the headlights probably don't go through the headlight switch, not back in 79, but the heater blower might. The way to tell would be to see if there is a fuse labelled for the heater, and check with a voltmeter whether is has 12v to it with the ignition switch off then on. My wiring diagram for a 1973 chassis shows a fuse for the heater, connected through the ignition -accessory- circuit, but the diagram doesnt show any wire connected from the other end of the fuse.
On my 72 D22 this fuse supplies the heater, which is therefore powered by the engine battery.
I got a spare ignition switch to carry with me, simply because the original one is 31 years old in my case. It is the electrical part of the switch, not the keyset part, and in an emergency I would connect it via the cable that sticks out of the steering column, and turn it on with my fingers.