Does anybody know the part number and or name of the electrical units tucked into behind the driverside storage area in a 72 ranchero. I think they r relays for rear tail and brake lights I want to replace with new ones. Not sure what to look up Thanks in advance Butch
There are 3 relays on the Ranchero at that location, and they were ONLY on Rancheros that were built with the Factory Trailer Towing package. Here is the part number from the MPC, please note that 3 are required to replace all and they are the same part number: Here is the wiring diagram for those interested: Here is the connector chart with wiring color codes to permit you to verify these are the relays in question:
Do u know. R they need to make system work, If they were there from beginning .? I'm not really interested in towing anything .But wonder do they complete a brake lite circuit then ?
Not needed to make system work, the wiring to lights is from the main 14405 harness, the relays are a supplemental harness that passes direct to the plug to connect the appropriate lighting controls to the trailer via it's connector. The only thing that would make this interfere with the proper operation of the car lighting would be if one or more of the wires to the relays were dead shorted.
Ok. Great. Thanks for info. I've got a issue somewhere ,I Have the lights in fornt working ,And only pass side tailight which stays on but does work when brake is pressed. I'm gonna start by seperating fuse block. Check grounds Then put in all new switches .I put in a new 1973 torino turnsignal switch which looked the same except the flasher button was round. And new brake light switch. But anyway Thanks again Butch
The fuse block isn't likely where your problem is - suggest you check the main 14405 harness connector which is under the driver's feet, under the carpet and under a protective sheet metal panel, that is where the dash wiring connects to the wiring harness that runs to the back lighting - you can also check for current from the dash harness at that connector, turn on your lights and check each wire with a Volt meter (positive lead to color coded wire for each light, negative to the black). Check the continuity of the wiring from the connector back to each of the lighting wires at the back. I'd check at the connector the voltage from the main harness, and then check for continuity working toward the back of the car (were it mine and I had the problem you describe). There is one additional connector for the wiring, a plug back by the fuel filler pipe that connects a cross vehicle harness that feeds the right side of the car and also has the fuel sender wiring. I've seen breaks in the wiring near the cubby where the wiring passes from under the carpet and runs into the inner void of the quarter panel, there are a couple of areas that present chafe hazards. FWIW, I'd test the wiring at the easiest places to reach them (the aforementioned connector under the driver's feet carpet) and work it from there.
sorry, here the web site http://www.2040-parts.com/1973-ford-thunderbird-nos-relay-assy-part-d3sz-13a435-a-i507268/
