I'm about to throw this thing though the nearest window.
- I have an inop automatic antenna in my 87 Jag xj6. Before I started, I could hear the motor running when I turned the radio on and off, and there is a delay relay that I can also hear click.
- The antenna mast was bent and the plastic cord broken. I have replaced both.
- Then the motor would work but the antenna wouldn't go up, because a guide in the case was broken. CA glue didn't hold so I bought a different case on eBay that had an unbroken guide.
- Reinstalled everything from my existing case to the new case.
- I have verified that I have plugged the wires in the same way they were when they came out.
- and now the motor doesn't turn. GRRRRR!!! (but it does get hot...)
As far as I can tell, the only part difference between the working motor and the non working motor is the brush holder, and I'm using the one from the 'parts case' because the brush holder that I had in the working motor had actually worn one of the brushes away completely, and was using the spring as a brush. The shaft, windings, magnet case, etc is all from the working motor I had.
I have verified that the motor can spin when I grab it with pliers, but it isn't easy to turn, I suspect it is the magnets though and not a physical contact issue - maybe?
There are limit switches and a relay built into the motor itself, but taking them out of the electrical system I have 2 wires (one to each brush, brushes are 180deg apart on the shaft), the shaft is where the windings are, the magnets are in the metal motor housing which bolts to the case, and then I can also ground the case (there is a ground strap and I noticed before that if it isn't connected the motor will not work). This motor has to be able to go both ways, to move the antenna up and down. I have also verified that the brushes are connecting with the windings.
So, my question is, how should I bench test this motor? Is it like 12V+ to one brush and case ground to go one direction and then 12V+ to the other brush and case ground to go the other way? Or would it be 12V+ to one brush and ground to the other brush and vice versa to reverse direction? What in the world could be the reason the motor isn't turning? I have everything greased up well and turning the whole assembly by hand is easy.
It just occurred to me that I might have the magnet housing on 180degrees backward...
Robbie (Forum Supporter) said:
It just occurred to me that I might have the magnet housing on 180degrees backward...
Well I'll be chili dipped.
It appears that this may have been the issue. Motor is turning now on the bench, need to carefully re-assemble the spool and install on the vehicle to see what happens.
Glad we could be of help.
Stampie said:
Glad we could be of help.
Not so fast.
The motor is now working when I apply 12v straight to the brushes, but still isn't working through the limit switch and reversing relay. Grrr.
There seems to be a significant (150ohm) resistance in the reversing relay, which I can't imagine helps. Alas, I have 2 reversing relays and they both read the same... So that either checks out or both are blown.
More progress.
I figured out the reversing relay was the issue. One of the 4 contactors wasn't contacting well.
After a little sandpaper, the whole thing worked!!! I got it to go fully up and down a few times just loose in the trunk.
Also, I figured out the motor was running backward. It would seem jag switched wire colors between j85 and j86... (I'm using everything from j86 except the brushes and brush plate from j85).
Unfortunately, after I started installing it back in the car, it jammed again on the way up or down. I need to take it back apart but I think the weed eater line I'm using isn't quite good enough.
As a fun bonus, I noticed that the only thing that shuts off power to the motor is the limit switch at either end of the motor travel. Therefore when the motor jams, there is nothing to "shut off" power to the motor, and the motor sits there at full stall torque (and current).
And that stall current happens to be just less than 15 amps. And the antenna motor gets super hot, sitting right next to fuel lines and the fuel pump in the trunk.
Fun times!
At this point, I'm pretty frustrated with the whole thing. I don't really want to retrofit an OEM antenna from a different model or try and fab in a new aftermarket 'universal' antenna of dubious quality. Nor do I want to switch to a fixed antenna. Nor do I want to go without an antenna.
But I am worried the factory design is a real fire risk and I dunno if I'll be able to source the right parts to make it really reliable.
Grrrr.
In reply to Robbie (Forum Supporter) :
The Lexus power antenna in my race car( sorry I tossed it ) seemed factory and worked fine.
The factory acknowledged the original design was defective and updated it but I'm sure some of that old stock is still around. So even ordering a new one is no assurance of getting a good working one.
The only reason I know that tidbit is the book Saving Jaguar by David Egan. But how close Jaguar was to going out of business and what it took to save it is a fascinating read.
ok, I'm hoping all of this is finally behind me.
I finally decided to plunk down for an aftermarket unit that is "generic" but at least has the remote motor like the jaguar stock one. And it was less than $100 on eBay with tax and shipping, and I had just sold some other parts so woo.
Anyway. It looks quite similar
But man what an awful and fiddly job. This is exactly why I wanted to stay with jag parts. Everything was close to right but everything was wrong.
I had to modify the bracket to hold it (bolt holes are same, but the distance between them is different by like 3/16ths - so I needed to slot the holes).
The mast is like 1/4 inch longer, so it doesn't install without disassembly and then reassembly inside the rear quarter panel - underneath the brake light. Lovely. The part goes through a small channel behind the bumper and then with the jag one there is the perfect amount of space to swing it up and bolt in. This new one is just to long to make the swing.
The mast is also about 1/8th inch smaller diameter. Which means you have to futz about to get the nice jag chrome top mount to fit instead of the black plastic ones that come with the kit. Also it means the braket that holds the mast will be too big and needs to be adjusted to get it to hold the mast securely.
At least the wiring was easy. And now the mast works great.
Grr grr grr get grr.
Done, finally!!!
In reply to Robbie (Forum Supporter) :
Well, what was the fix?
thatsnowinnebago said:
In reply to Robbie (Forum Supporter) :
Well, what was the fix?
I could get the jag antennas working but ultimately I was really uncomfortable with the failure mode when they jam (stalling the motor and pulling high current and getting nice and hot in the closed trunk cavity right next to the exposed fuel lines and fuel pump).
So I got a new aftermarket one that seems pretty reputable, and installed it, even though it is 'generic' and not a very good fit.
In reply to Robbie (Forum Supporter) :
Well done. You did something the factory failed to do at least until the mid to late 80's.
It was things like that that had the Jaguar company on the chopping block.
If Jaguar hadn't broke free of BLMH to become independent, bought the Body plant, and started improving the quality of their cars. It's likely they were going to fail. They were losing millions of dollars a year and that's with the government subsidizing them.
Lucas and other suppliers's business model was to sell Jaguar parts at the lowest possible price and plan on making profits off their replacements.
