When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
1970 coupe 350/4 speed. I've started diagnosing my inoperative wiper door and believe that I found the problem (or at least one of the problems). I pulled the electrical connector off of the tach solenoid and noticed it had 2 yellow wires going to one terminal of the connector but nothing to the other terminal. I checked my schematic and it shows there should be 2 light blue wires going to the second terminal. I pulled the instrument panel hoping to find a couple of stray light blue wires hanging around there, but no such luck. There are 2 light blue wires that exit from the nearby harness but those go directly to the wiper switch. I don't see any cut wires or butchered harnesses under there. Could someone please verify for me that the missing terminal wires are in fact supposed to be light blue, and if someone happens to have their dash apart, perhaps post a pic here of where those wires come from, i.e. from the main harness, are run individually from elsewhere etc. That would be a big help for, right now I don't know where to look.
Thanks Mooser, now I know for sure what's missing. Does anyone out there have any pics showing where these two blue wires exit the dash harness or know where they're routed from? I can't find any evidence of them ever having been there. I unwrapped a portion of the dash harness that had been re-wrapped and found no loose blue wires taped up in there, or any evidence of wires cut from the harness. I do wonder why that portion of the dash harness was re-taped though.
I can only say that on my 72 harness the one blue wire went into the same wrapped section as the two yellows did, there the split and one goes off to the fuse panel and the other goes to the relay under the center console along with the blue. The other blue went to the wiper switch itself
M
This is very strange. It's likely that for some bizarre reason, Bubba decided those wires didn't need to be there. Oddly enough he did a fantastic job of hiding all evidence that they were ever there. According to 2 different wiring schematics, one of the blue wires goes from the tach solenoid to the wiper switch, the other goes tach solenoid to wiper motor. I'm thinking of running wires directly to the correct terminals on each of these. Would they need to be fused independently from the fuse box? I guess it couldn't hurt, just to be on the safe side. Why Bubba, WHY??
On the 72 there is another blue wire that is tied in somewhere inside the harness which is the one that goes to the wiper motor. Does you're not use a relay as well?
M
On the 72 there is another blue wire that is tied in somewhere inside the harness which is the one that goes to the wiper motor. Does you're not use a relay as well?
M
Mooser, yes there is a wiper relay inside the center console. It has a yellow wire going to it from the tach solenoid and a blue to it from the wiper switch. Those are there, unmolested and in good condition. It's those 2 %&#@%!! blue wires that are supposed to connect to the tach solenoid that are driving me nuts. According to my schematics one of those wires should go from the solenoid to the wiper switch, the other from the solenoid to the wiper motor. Sure would like to know why the were removed and where they went! I spent another 45 minutes tonight inspecting the harnesses and still no sign of either of them...
Basically the same on my 72 except where they all joined.
The blue wire connects wiper motor, switch, solenoid and relay all together.
I can only wonder if something didn't work (relay?) and they bypassed all of it
M
Basically the same on my 72 except where they all joined.
The blue wire connects wiper motor, switch, solenoid and relay all together.
I can only wonder if something didn't work (relay?) and they bypassed all of it
M
Thanks for your help Mooser, I'm thinking the same. I had the console off last year and replaced the relay with a new one "while I was there". I know the new relay functions correctly as I tested it before installing it. Didn't check the old one though.
If I run wires directly from the solenoid to the correct terminals on the wiper switch and wiper relay, would they need to be fused independently from the fuse box?
Last edited by Majoho; Mar 21, 2022 at 12:21 PM.
Reason: spelling
The wiper system is on a fusible link rather than a fuse so it shouldn't need to have one added (unless the link was toasted)
(reference the note on the lower right about the singe vs double blue wires)
M
Thanks again Mooser!
I'll temporarily run a couple of wires from the t/solenoid to the motor and switch and see what happens. If that gets the solenoid working I'll run them permanently and then rejoice! Not without cursing bubba a few times though.
Will post results here when I've done this. May take a day or two though.
I think I'm making progress with this wiring situation. Would it be possible that this wiring connection could have been made at the factory? I don't think so but perhaps more experienced eyes could say otherwise?
If that's a bullet connector inside there then I'd say no, they did use a crimp connector to join 2 wires into 1 is several places but it was just a straight double-ended crimp
M
Well, I've spent a LOT of time studying wiring diagrams, tearing apart the LH and center instrument panels, probing wires, checking continuities,running temporary jumper wires, scratching my head and cussing to myself. I finally figured out what was missing and what needed doing. Ran the necessary wires,double and triple checked everything, taped up the harnesses, and put the dashes back in place(that was an adventure in itself-dash work, ugh). And just like that, my windshield wipers work perfectly. The cowl panel pops up, the wipers wipe both speeds, w/shield washer works, turn them off, they park and the cowl panel closes. What a great feeling to have that working properly for the first time! A nice sense of accomplishment too. A big thanks to Mooser for all your help and guidance!
Tach Solenoid Connector help
According to 2 different wiring schematics, one of the blue wires goes from the tach solenoid to the wiper switch, the other goes tach solenoid to wiper motor. I'm thinking of running wires directly to the correct terminals on each of these. Would they need to be fused independently from the fuse box? I guess it couldn't hurt, just to be on the safe side. Why Bubba, WHY?? 
I spent another 45 minutes tonight inspecting the harnesses and still no sign of either of them...
for all your help and guidance!