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Howesight
Samba Member
Joined: July 02, 2008
Posts: 3419
Location: Vancouver, B.C.
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 Posted: Wed Feb 11, 2015 3:58 pm Post subject: Re: 50 Amp fuse. |
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| vramsaran wrote: |
I have a problem with my 1990 vw ac system. That metal strip 50 amp fuse is melted along with some of the plastic that holds the scews. I used a modern day 50 amp and some alligator clips to see what would happen. Started to get really hot for some reason.
Could there be a short somewhere ? If so where should I start looking if you could guide me in the right direction it would be greatly appreciated.
Thanks in advance. |
The two evaporator fan motors, like the front heater fan motor, do get sticky over time as the oil dries out of the oil-impregnated bronze bushings and crud accumulates in those bearings and elsewhere. At the same time, the grounds start to acquire resistance. All of this adds up to turning the whole circuit into a giant resistor that overheats.
Doubling up the wire from the alternator to the 50 amp fusible link is an excellent cure for half the problem. The other half of the cure requires you to remove the evaporator fans and free up and lubricate them or simply replace them.
Those fan motors do have a huge draw if they are stuck. I doubt that you have a short.
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'86 Syncro Westy SVX |
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JudoJeff
Samba Member
Joined: May 24, 2013
Posts: 1179
Location: Near Springfield, MA
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| Posted: Wed Feb 11, 2015 6:28 am Post subject: Answers your question |
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This new post will help you find the answer:
http://www.thesamba.com/vw/forum/viewtopic.php?t=321941&highlight=
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1989 Vanagon GL Westfalia Camper, Burned up on 7/31/16.
1987 Vanagon GL Westfalia Camper, Bostig & Rebuilt, sold
1986 Vanagon GL Westfalia Camper, Bostig Sold May 10, 2021
1999 Ford GTRV Westfalia camper (30% bigger Westy layout) |
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MarkWard
Samba Member
Joined: February 09, 2005
Posts: 19052
Location: Retired South Florida
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| Posted: Thu Jan 29, 2015 7:37 am Post subject: |
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| 50 amps is a huge load. I would expect some warmth even under normal conditions. Best to get an amp meter with the range to measure 50 plus amps and see what exactly it is drawing. A direct short would take that fuse out very quickly. |
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JudoJeff
Samba Member
Joined: May 24, 2013
Posts: 1179
Location: Near Springfield, MA
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| Posted: Thu Jan 29, 2015 6:58 am Post subject: |
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It takes a lot to melt that fuse, so, yes, you have a short.
You'll just have to start tracing out the electrical system for the A/C system, there's no short cuts that I know of. You'll need the Bentley to do that.
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________________________________________
1989 Vanagon GL Westfalia Camper, Burned up on 7/31/16.
1987 Vanagon GL Westfalia Camper, Bostig & Rebuilt, sold
1986 Vanagon GL Westfalia Camper, Bostig Sold May 10, 2021
1999 Ford GTRV Westfalia camper (30% bigger Westy layout) |
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vramsaran
Samba Member
Joined: January 30, 2010
Posts: 43
Location: Deltona, Florida
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| Posted: Wed Jan 28, 2015 6:27 pm Post subject: 50 Amp fuse. |
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I have a problem with my 1990 vw ac system. That metal strip 50 amp fuse is melted along with some of the plastic that holds the scews. I used a modern day 50 amp and some alligator clips to see what would happen. Started to get really hot for some reason.
Could there be a short somewhere ? If so where should I start looking if you could guide me in the right direction it would be greatly appreciated.
Thanks in advance. |
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Howesight
Samba Member
Joined: July 02, 2008
Posts: 3419
Location: Vancouver, B.C.
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| Posted: Sat Apr 26, 2014 9:07 pm Post subject: |
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Here is a pic. You can see the references to this at pp 87.4 to 87.5 in your Bentley manual. The wiring diagram is at pp 97.140 and 97.141.
There are 3 relays in the pics below. The centre one is the relay for the evap fans.
The metal strip just below the centre relay is the 50 amp So fuse. The connections at the So fuse sometimes melt the plastic adjacent to the screws that hold the fuse in place. Check that.
To get power to the evap fans, a lot of things have to occur:
1. AC switch on and turned to max cool;
2. Fuse S12 must be good (15 amps)
3. AC relay has power and is functional;
4. Evaporator switch properly connected and switched on;
5. Evap fan fuse S51 (20 amp) not blown;
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'86 Syncro Westy SVX |
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Steve M.
Samba Member
Joined: July 30, 2013
Posts: 6933
Location: Fort Lauderdale, Fl.
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| Posted: Sat Apr 26, 2014 9:05 pm Post subject: |
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...
Last edited by Steve M. on Sat Apr 26, 2014 9:10 pm; edited 1 time in total |
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blemon
Samba Member
Joined: January 16, 2014
Posts: 106
Location: WV
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| Posted: Sat Apr 26, 2014 6:24 pm Post subject: |
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| Can someone post a photo of the fuse SO 50A and evap fan relay? |
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blemon
Samba Member
Joined: January 16, 2014
Posts: 106
Location: WV
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| Posted: Sat Apr 26, 2014 1:04 pm Post subject: |
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| Still researching and working on this bit by bit. |
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blemon
Samba Member
Joined: January 16, 2014
Posts: 106
Location: WV
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| Posted: Fri Apr 25, 2014 1:10 pm Post subject: |
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OK, we replaced the fuses shown in the photos. Compressor comes on (still sounds awful). Back fans still don't work so we're not sure if the evap works.
Any suggestions for figuring this out?
Nothing happened in the area where the evap and back fans are. |
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blemon
Samba Member
Joined: January 16, 2014
Posts: 106
Location: WV
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| Posted: Wed Apr 23, 2014 7:24 pm Post subject: |
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| cellerdoor wrote: |
2. Nostalgic Air has reasonable compressors, dryers and I think expansion valves. Might be able to get all three at one place. Likely the Sanden 709 is the right compressor for your year. How do the hoses connect to the compressor? Directly into the back?
3. Might as well change your belts at this time if it hasn't been done recently. GoWesty has a nice package.
Curious about jumping the compressor. I assume your shop knows that a lack of charge will trip the low pressure switch on the system and it wont come on unless you jump it. Are you sure the compressor is bad? This also might relate to the fan not coming on but I have no knowledge here.
Where in WV? I found my van near Wheeling. |
Thanks for this.
We'll have to actually look at the compressor to see how the hoses connect. My husband was down there today and he can't picture it right now. We'll look at the 709 first to compare.
Compressor: it came on with the jump and then made crazy loud grinding sounds. The dude said, "it don't look good. it's real noisy." He's been working on these things for a long time. His shop has been there since I was a kid. I will take his word for it.
After reading some of the other posts, I bet the electrical issue with the back fans is just a fuse since the front fans work. But every time we say "just" this or "just" that, we get an unpleasant reality check.
We are in Morgantown. Actually found the van on the Samba and flew up to get it. Aside from the AC and an exhaust leak that shouldn't be too bad (fingers crossed), it's in great shape.
Love Wheeling. Such a gorgeous old town. |
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cellerdoor
Samba Member
Joined: July 10, 2012
Posts: 406
Location: Fairfax Virginia
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| Posted: Wed Apr 23, 2014 4:53 pm Post subject: |
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| blemon wrote: |
UPDATE:
Good news: they have a guy who cuts hoses so we'll save a lot there.
Bad news: something electrical is wrong. The back fans don't work (and they had to jump start the original compressor). Perhaps the ok news about this is that my husband can do electrical work in the house.
Would love some feedback on two things:
1. links to parts to buy. Found a couple on the earlier thread. We can save by buying the parts and bringing them to him.
2. any ideas on the electrical? front fans are working fine.
We will take out the cabinets ourselves and keep them here while it's in the shop. We decided this is one thing we might not DIY the whole thing. |
If I'm reading this correctly you need to buy a new receiver/dryer, expansion valve and compressor and your repair shop is making new hoses. Questions back:
1. Are they reusing the old a/c hose fittings or providing new? Id recommend new fittings if you can swing the $100. Don't have the hoses/fittings made up until you know what your compressor connections look like since it may change your fittings at the compressor.
2. Nostalgic Air has reasonable compressors, dryers and I think expansion valves. Might be able to get all three at one place. Likely the Sanden 709 is the right compressor for your year. How do the hoses connect to the compressor? Directly into the back?
3. Might as well change your belts at this time if it hasn't been done recently. GoWesty has a nice package.
Curious about jumping the compressor. I assume your shop knows that a lack of charge will trip the low pressure switch on the system and it wont come on unless you jump it. Are you sure the compressor is bad? This also might relate to the fan not coming on but I have no knowledge here.
Where in WV? I found my van near Wheeling.
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campism
Samba Member
Joined: September 07, 2007
Posts: 4710
Location: Richmond VA
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| Posted: Wed Apr 23, 2014 3:14 pm Post subject: |
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Here's the thread that I find inspiring:
http://www.thesamba.com/vw/forum/viewtopic.php?t=365626&highlight=rebuild+project
Our '87 Westy had a complete A/C system but it blew hot air when we got the van. Previous owners had made various attempts to get it working reliably but it always crapped out. Soon after purchase I took it to a local A/C place that had installed air in my '85 Nissan pickup years ago and they gave me a $2000 estimate to fix the Westy so I tried a $40 R134a conversion that works acceptably for a season before it leaks down. I need to recharge annually but will eventually rebuild the system with new hoses.
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'87 Westy in Wolfram Grey Metallic, tragically crushed by a falling hickory tree in my own driveway and now gone, leaving me Vanagonless and with no plans to replace it, alas. |
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blemon
Samba Member
Joined: January 16, 2014
Posts: 106
Location: WV
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| Posted: Wed Apr 23, 2014 1:47 pm Post subject: |
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UPDATE:
Took JJ in to the shop today. Really nice guys. Seem to know what they are talking about.
Basically the whole system is shot. We need a new compressor and expansion valve. They filled it and did a dye test with stop leak.
Good news: they have a guy who cuts hoses so we'll save a lot there.
Bad news: something electrical is wrong. The back fans don't work (and they had to jump start the original compressor). Perhaps the ok news about this is that my husband can do electrical work in the house.
Would love some feedback on two things:
1. links to parts to buy. Found a couple on the earlier thread. We can save by buying the parts and bringing them to him.
2. any ideas on the electrical? front fans are working fine.
We will take out the cabinets ourselves and keep them here while it's in the shop. We decided this is one thing we might not DIY the whole thing. |
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morymob
Samba Member
Joined: November 09, 2007
Posts: 4683
Location: east-tn
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| Posted: Sun Mar 30, 2014 5:20 am Post subject: |
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| Any AC with a leak will get worse in time as the gas gets lo and will totally quit, at some press level the comp won't be allowed to run. U have same sys as my syncro & after dropping and cleaning out the evap unit(about 1/2 stopped up, air flo, it will get as cold as u can stand. Orig unit has plenty of capacity 4 cooling IF u do some maint, bad door seals ? front vent shuts off etc?.Mine has been converted to Red-Tek by the way & add a can of their hose conditioner at the same time, 3 yrs now & no gas added. |
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blemon
Samba Member
Joined: January 16, 2014
Posts: 106
Location: WV
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| Posted: Sat Mar 29, 2014 5:46 pm Post subject: |
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Ok, did some research.
Here's what we know:
As early as 29k miles in, the first owner was charging the freon and continued to do so every year 1/2 - 2 years until he sold it. It doesn't look like he did anything else.
So any clues why it wasn't cold enough so early on?
But we'll start with the hoses and go from there.
Any reason why the previous poster would remove the cabinet instead of threading them through? |
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Howesight
Samba Member
Joined: July 02, 2008
Posts: 3419
Location: Vancouver, B.C.
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| Posted: Fri Mar 28, 2014 2:26 pm Post subject: |
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| blemon wrote: |
These are really helpful. Thanks so much.
We're going to try to determine what went wrong initially based on the receipts we have from the previous owners (we are #3!).
We'll go from there and decide. There is a limit to the time we have for the DIY but Mr. Lemon seems to be able to fix just about anything so I know he can do it.
Will get back to those of you who offered! |
If Mr. Lemon can remove all the AC hoses and bring them to an AC shop, they can rebuild all of them with new, state-of-the-art barrier hose. Shop around a bit and you are sure to find a reasonable price. I made my own hoses, but I was installing a front AC system I built from scratch. ( See here: http://www.thesamba.com/vw/forum/viewtopic.php?t=535444&highlight=diy+front+air+conditioning )
The factory system can be revived fairly easily, in my opinion - - at least compared to the work of starting from scratch. As you disassemble the system, note whether the oil in the hoses and components appears to have any foreign matter in it. You are looking for signs of aluminum slurry and/or Teflon parts. These are the tell-tale signs of a compressor failure. The pistons in the factory compressor are aluminum but, IIRC, use Teflon piston rings. Overpressure, under-lubrication and overheating cause the Teflon to disintegrate and under-lubricated metal-on-metal contact that creates the aluminum slurry. If there is no sign of either, you may just have a perfectly usable compressor! The Bentley manual specifies a procedure for checking the compressor which involves running the AC at high pressure by blocking the cooling air to the condenser. Obviously, this can only be done after you have done all your re-hab work and installed the refrigerant.
When I first started playing with AC systems on other vehicles years ago, I replaced more than one perfectly-usable compressor due to my ignorance of how the system actually worked. Live and learn . . .
There are a few companies now that sell in-line filters to filter out foreign matter from circulation in your expensive AC system. These are worth your consideration. Here's a link to a write up a BMW guy posted for his inline filter install:
http://www.e46fanatics.com/forum/showthread.php?t=686807
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morymob
Samba Member
Joined: November 09, 2007
Posts: 4683
Location: east-tn
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| Posted: Fri Mar 28, 2014 1:02 pm Post subject: |
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| Air didn't work on any of 4 that i owned when bought, most needed was compressor on one was missing. None needed all the stuff that makes up the air sys.All driven at least 3 yrs and only the current one, owned 10 yrs+ now finally had the evap unit dropped and cleaned, was going to drop anyway as i had to repair broken ends. I do all my own work and will soon be adding air to my westy as it didn't come with one.(bosses orders if she is to ride inside in summer), me not a problem. If doing all that floats your boat, go 4 it. My 2-cts. |
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Ahwahnee
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Joined: June 05, 2010
Posts: 10294
Location: Mt Lemmon, AZ
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| Posted: Fri Mar 28, 2014 9:32 am Post subject: |
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| rsxsr wrote: |
| ...it may require multiple trips to the shop with some expensive parts, but eventually will be reliable. |
That was my biggest concern when I chose to farm out the work. In the end it was just the one 'visit'... a long visit.
I did not rush them (and they took quite awhile) to give them plenty of time (and expected them) to thoroughly test for leaks both before and after charging over the course of several days.
I also opted not to do just parts of the system (e.g. 'this hose looks okay') as I knew many potential failures would be hard to get at later and cheaper to replace now.
I did choose to keep the compressor (newish compared to the van) and evap (original) as they checked out fine -- so far that seems to be okay. |
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MarkWard
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Joined: February 09, 2005
Posts: 19052
Location: Retired South Florida
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| Posted: Fri Mar 28, 2014 8:44 am Post subject: |
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| I would add, AC is a commitment. You need to see it through. In other words, it may require multiple trips to the shop with some expensive parts, but eventually will be reliable. |
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