A/C

A/C question
I didn't want to bother putting this out on the forum but I did in case its of use to anybody else. There are 2 small black wires that run to terminate on my AC compressor. One terminates on the side of the unit and the other appears to terminate behind the pulley. Both of them feed into a loom that terminates in a weather pack connection less than a foot away.

My question is this. The one that terminates on the side of the compressor is a little rusty and I can only assume the the other one that terminates behind the pulley is just as bad. I know there is a HUGE benefit to upgrade your grounds because the electrical system is under engineered. Is this another one those weak links? Would I be better off eliminating the weather pack connection and using larger wire?

96 HO, AW4, NP231, D30, C8.25

The two wires are Clutch Ground and Clutch engage.
Are you having issues with the AC not working?

I dissagree with the assertion that the Electrical System was "Under Engineered".

WB9YZU said:

The two wires are Clutch Ground and Clutch engage.
Are you having issues with the AC not working?

I dissagree with the assertion that the Electrical System was "Under Engineered".

Click to expand...

I am not having issues with my A/C as of yet other than the needle plummeting everytime I turn it on. Yes it works its way back up eventually. Yes, I know the fan kicks on at the same time. However I have recently upgraded and refreshed my mains and I was wondering if there was a subject matter expert out there that might be able to give me a little more insight. Would it be benificial to upgrade these wires?

Sir, you are the first individule that I has openly admitted that you disagree with the assertion that the electrical system was/is under engineered. No disrespect, just help me understand. I wouldnt be here if I didnt need the help....

Sounds like your belt is still too loose. The Serpentene belt sould just about twang like a banjo string when you pluck it. The way I know I have them tight is to kick on the headlights and the AC just off a start. If it squeels, it's too loose and I get in there and wrench away and repeat the test.

The entire load on that wire is the Clutch. It draws a some, but it's not required to be heavy guage wire.

I have found that though we may not see the "Why", the system is designed to perform a certain mission: To keep the car reliable for as long as possible and that an Engineer will ofen sacrifice performance for reliability.

We on the other hand, are constantly looking for some way of improving on what the factory did.

WB9YZU said:

Sounds like your belt is still too loose. The Serpentene belt sould just about twang like a banjo string when you pluck it. The way I know I have them tight is to kick on the headlights and the AC just off a start. If it squeels, it's too loose and I get in there and wrench away and repeat the test.

The entire load on that wire is the Clutch. It draws a some, but it's not required to be heavy guage wire.

I have found that though we may not see the "Why", the system is designed to perform a certain mission: To keep the car reliable for as long as possible and that an Engineer will ofen sacrifice performance for reliability.

We on the other hand, are constantly looking for some way of improving on what the factory did.

Click to expand...

Thanks, Ill tighten it up a little more when I get back to the garage. You made my point for me as well, would there be any noticeable improvement by upgrading those wires.

I plan on cleaning up that ground location anyway.

Cleaning grounds never hurts, especially on an older vehicle.

I can't see where upgrading those wires would be an advantage. As I mentioned, they only run the AC Clutch.

Clean the connector, apply a light coating of dielectric grease to it's boot, and slide it back together. Consider it molested and move on to more interesting wires :jester:

Ron

WB9YZU said:

Sounds like your belt is still too loose. The Serpentene belt sould just about twang like a banjo string when you pluck it. The way I know I have them tight is to kick on the headlights and the AC just off a start. If it squeels, it's too loose and I get in there and wrench away and repeat the test.

The entire load on that wire is the Clutch. It draws a some, but it's not required to be heavy guage wire.

I have found that though we may not see the "Why", the system is designed to perform a certain mission: To keep the car reliable for as long as possible and that an Engineer will ofen sacrifice performance for reliability.

We on the other hand, are constantly looking for some way of improving on what the factory did.

Click to expand...

The engineers and the bean counters work hand in hand. Both Chevy and Chrysler redesigned their heads to lighten them and save a few ounces of steel, we all know how that turned out. Same thing with the wiring, the price of copper goes up, the size of the wire goes down. Many of the redesigns are for ease of manufacturing, cost saving on materials and weight factors to try and meet EPA goals. Longevity is a secondary goal if a goal at all, most vehicles are designed for a seven year lifespan. Jeep used to build for longevity, then Chrysler took over. I live in salt country, as a whole, other than the paint, my 88 is in better shape than my 96.

And to answer the original question, the wire size is only as good as the thinnest section, other than a little line loss, adding a thicker wire to a thinner wire is not going to help much if any. Having said that, a larger wire does help some as a heat sink and may absorb more heat before failure than a thinner wire.

8Mud said:

The engineers and the bean counters work hand in hand. Both Chevy and Chrysler redesigned their heads to lighten them and save a few ounces of steel, we all know how that turned out. Same thing with the wiring, the price of copper goes up, the size of the wire goes down. Many of the redesigns are for ease of manufacturing, cost saving on materials and weight factors to try and meet EPA goals. Longevity is a secondary goal if a goal at all, most vehicles are designed for a seven year lifespan. Jeep used to build for longevity, then Chrysler took over. I live in salt country, as a whole, other than the paint, my 88 is in better shape than my 96.

And to answer the original question, the wire size is only as good as the thinnest section, other than a little line loss, adding a thicker wire to a thinner wire is not going to help much if any. Having said that, a larger wire does help some as a heat sink and may absorb more heat before failure than a thinner wire.

Click to expand...

Thanks for the explanation Mud!

Yesterday, 23:49
5-90
#215
Join Date: Mar 2003
Location: Hammerspace
Posts: 18,677


Re: A/C question
Quote:
Originally Posted by bugout
I didn't want to bother putting this out on the forum but I did in case its of use to anybody else. There are 2 small black wires that run to terminate on my AC compressor. One terminates on the side of the unit and the other appears to terminate behind the pulley. Both of them feed into a loom that terminates in a weather pack connection less than a foot away.

My question is this. The one that terminates on the side of the compressor is a little rusty and I can only assume the the other one that terminates behind the pulley is just as bad. I know there is a HUGE benefit to upgrade your grounds because the electrical system is under engineered. Is this another one those weak links? Would I be better off eliminating the weather pack connection and using larger wire?

Those wires are for your aircon compressor clutch - it's an electromagnetic clutch that engages when the compressor is needed, or when the system just needs to circulate for a bit. Without the clutch energised, that pully is merely an idler.

It would be beneficial to clean that ground - to your air conditioning. There is no real need to upgrade that wiring, nor will a failure there have a negative effect anywhere else (apart from your aircon won't work anymore.) When the compressor is pulled to be discarded, it gets replaced with an idler pully and the wiring may simply be terminated. If the compressor would get used for OBA, the OEM wiring would be terminated, and the compressor clutch wired to be switched manually. ("Terminated" means the wires separated and insulated - either by removal of the OEM connector, or by installation of a "blind" plug. A resistor may also be wired between them, but I don't know enough at the moment to tell you what would be a proper "dummy load" for that circuit.)

Feel free to post this into your thread, if you like.
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From 5-90

Those wires are for your aircon compressor clutch - it's an electromagnetic clutch that engages when the compressor is needed, or when the system just needs to circulate for a bit. Without the clutch energised, that pully is merely an idler.

It would be beneficial to clean that ground - to your air conditioning. There is no real need to upgrade that wiring, nor will a failure there have a negative effect anywhere else (apart from your aircon won't work anymore.) When the compressor is pulled to be discarded, it gets replaced with an idler pully and the wiring may simply be terminated. If the compressor would get used for OBA, the OEM wiring would be terminated, and the compressor clutch wired to be switched manually. ("Terminated" means the wires separated and insulated - either by removal of the OEM connector, or by installation of a "blind" plug. A resistor may also be wired between them, but I don't know enough at the moment to tell you what would be a proper "dummy load" for that circuit.)

Feel free to post this into your thread, if you like.[/QUOTE]

Kelly - The A/C Clutch is unsupervised.

8Mud - LOL! The old saw about Damler killing AMC's, then Chrysler's quality!
AMC had the worse quality of the 4 remaining American Manufactures (your '88). Seems to me that Chrysler actually inproved the fit/finish, got rid of the Renix fuel management system, and added features to the vehicle (Your '96).


As far as the head design on late model XJs, ALL manufactures have had issues here and there with heads, especially when they try and increase port sizes to accomidate our thurst for more power and meet every increasing EPA standards. When I was using late 70's LA Engines I don't know how many appearantly good heads I tossed because they didn't pass magnafluxing.

WB9YZU said:

Cleaning grounds never hurts, especially on an older vehicle.

I can't see where upgrading those wires would be an advantage. As I mentioned, they only run the AC Clutch.

Clean the connector, apply a light coating of dielectric grease to it's boot, and slide it back together. Consider it molested and move on to more interesting wires :jester:

Ron

Click to expand...

Sir,

I have just recently got over my fear of electricity by upgrading the grounds. I think it wierds me out because I cant SEE it! :flamemad:

bugout said:

Sir,

I have just recently got over my fear of electricity by upgrading the grounds. I think it wierds me out because I cant SEE it! :flamemad:

Click to expand...

LOL!
The nice thing about auto electronics it that, generally speaking, you don't need to be a super genious to work with it

Keep having fun!

Ron

DO NOT rely on the dash voltage gauge (or any other on the dash for that matter) to be accurate. They are notorious for not reading true. This is a wiring issue to the dash, not an under rated charging system.

Simply turning on the blower will cause my volt gauge on the dash to show low voltage. I know this not to be true as I have confirmed true voltage with a DVOM.

This has been the case with 3 xj's now.