A/C issue

User avatar
del_TJ
BSJ 101 Planning Commitee
Posts: 381
Joined: Thu Aug 26, 2010 1:19 pm
Jeep Year: 1998
Jeep Model: TJ Wrangler
Location: Newton, MA

A/C issue

Unread post by del_TJ »

Can anyone help me work through this?

The a/c clutch engages and cycles normally during the two low fan speeds but not on either of the two high speeds. When it’s working the line into the evaporator gets icy cold and the air is cold as well, so it doesn't seem like a refrigerant problem. Blower motor works normally at all speeds.

What should I try next?
User avatar
Kurt
BSJ Member
Posts: 4203
Joined: Wed Dec 23, 2009 11:53 am
Jeep Year: 1992
Jeep Model: YJ Wrangler
Real Name: Kurt K.
Location: Pepperell, MA

Re: A/C issue

Unread post by Kurt »

What happens or doesn't happen at the higher fan speeds? Compressor not cycle at all?
"Build It, Run It, Break It, Improve It, Repeat!"
NEA Treasurer 2016, 2017, 2018, 2019, 2020
BSJ Treasurer 2020
User avatar
del_TJ
BSJ 101 Planning Commitee
Posts: 381
Joined: Thu Aug 26, 2010 1:19 pm
Jeep Year: 1998
Jeep Model: TJ Wrangler
Location: Newton, MA

Re: A/C issue

Unread post by del_TJ »

At high speed the compressor doesn't cycle. Does cycle at low speeds.

I guess it might be the speed switch since the blower resister is bypassed at high speed if I understand it correctly.
User avatar
Fcgeek
BSJ 101 Planning Commitee
Posts: 128
Joined: Thu Mar 10, 2016 11:03 pm
Jeep Year: 2004
Jeep Model: TJ Wrangler
Real Name: Chuck
Location: Ashburnham Ma

Re: A/C issue

Unread post by Fcgeek »

Have you tried all this while sitting still or moving. My AC vent has a vacuum leak somewhere and under acceleration feels like no AC because the AC is coming out of defrosters. You might be experiancing a similar issue.
2004 TJ Rubicon (Hooptie) Kick A$$ Grill
User avatar
del_TJ
BSJ 101 Planning Commitee
Posts: 381
Joined: Thu Aug 26, 2010 1:19 pm
Jeep Year: 1998
Jeep Model: TJ Wrangler
Location: Newton, MA

Re: A/C issue

Unread post by del_TJ »

I first noticed the issue while driving but then figured out the a/c wouldn't engage while standing/idling under high fan. The a/c works fine under low fan while driving or standing.

Went to Autozone but their replacement blower switch doesn't have the correct knob arm on it :doh:
User avatar
Frank
Frankie BSJ Member
Posts: 4145
Joined: Sun Dec 27, 2009 8:54 am
Jeep Year: 1974
Jeep Model: CJ5

Re: A/C issue

Unread post by Frank »

Thats a weird problem. Id check to see if there is a loss of voltage at the comp when switched to the higher speeds. That would start to indicate the switch and or relays. The working while driving and not at a stop ????? Blows me away. Id push in the clutch and rev it up . FjR68
User avatar
nhdcoye
BSJ Member
Posts: 932
Joined: Wed Jan 06, 2010 9:04 pm
Jeep Year: 1992
Jeep Model: YJ Wrangler
Real Name: Better known as Dave

Re: A/C issue

Unread post by nhdcoye »

del_TJ wrote:At high speed the compressor doesn't cycle. Does cycle at low speeds.

I guess it might be the speed switch since the blower resister is bypassed at high speed if I understand it correctly.
I had a similar problem years ago in my saturn. Turns out it was the resistor pack/board. My low speed fan did not work the 2 higher speeds did. on low the AC indicator illuminatedbut not on high, compressor would cycle on/off on low but not on high. Swapped out the Bd and all was fine:-)
92 YJ 6Cyl > 3 " lift, ford 8.8 SOA on XJ springs with Aussie out back, D30 with alloy 30's and ARB up front 4:56. 35 MTR's, 10K Winch, SYE ,traction bar, onBd Air and lots of gently used skids
User avatar
del_TJ
BSJ 101 Planning Commitee
Posts: 381
Joined: Thu Aug 26, 2010 1:19 pm
Jeep Year: 1998
Jeep Model: TJ Wrangler
Location: Newton, MA

Re: A/C issue

Unread post by del_TJ »

Update. To clarify, a/c cycles with fan on low driving or standing, a/c clutch doesn’t engage with fan on high while driving or standing.

Bought a Mopar 99-04 3 speed switch and it fixes the problem. BUT, speeds are Low-Med-High-OFF (not a 4 speed switch). I’d have to get creative with a dremel to make the switch work. Old on left, new on right. The shaft is too long. No smartas$ jokes please :lol:

No one make a 97-98 4 speed switch. The original speeds are Low-Med1-Med2-High. The only option is to buy the whole HVAC control face unit with a new switch for around $100. New Mopar 99-04 switch was $25.


What would you do?
IMG_1589.jpg
User avatar
Modeler
BSJ Member
Posts: 974
Joined: Sat Oct 16, 2010 5:37 pm
Jeep Year: 2005
Jeep Model: LJ Wrangler

Re: A/C issue

Unread post by Modeler »

Any chance someone like Collins Bros or one of the other secondhand Jeep parts dealers (like Second Life Jeep) many have them?
Speed costs money, how slow do you want to go?
User avatar
RalphTomaccio
BSJ 101 Planning Commitee
Posts: 1251
Joined: Sun Sep 29, 2013 9:50 am
Jeep Year: 2012
Jeep Model: JK Wrangler
Location: Slatersville RI

Re: A/C issue

Unread post by RalphTomaccio »

I think if the high setting on the new switch put out the same velocity as the high setting on the old switch, I would learn to live with the 3 speed switch. If it put out less, I'd be tempted to find the 4 speed.
User avatar
Frank
Frankie BSJ Member
Posts: 4145
Joined: Sun Dec 27, 2009 8:54 am
Jeep Year: 1974
Jeep Model: CJ5

Re: A/C issue

Unread post by Frank »

Usually the control board controls the max fan output by letting the compressor cycle on AC , with any fan speed . MAX-Air locks the compressor and delivers one more speed to the blower not switched. 3 speed / 4 speed , might not make any difference in blower total speed , just how big the jumps are from one to high . See if your friends know anyone in HVAC . They may have a flow meter you could borrow. We used it to balance central air complaints of this room is colder or this room wont cool as well. The clarification statement would have me looking at the switch also. What about getting the switch out of a bone yard. FjR68
Post Reply