Blower intermittently fails to turn on - JeepForum.com
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post #1 of 25 Old 10-20-2018, 07:11 AM Thread Starter
iconoclasthero
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Blower intermittently fails to turn on

This just popped up a week ago...and while I wouldn't really have noticed the problem much over the summer, the blower was working this fall.

I pulled the fuse and checked it, scraped off any corrosion on the contacts and it didn't solve the problem...it is intermittent. One thing that I've noticed is that sometimes if I turn the key off and on (fun to while driving!), I can sometimes get it to turn on.

The blower and the resistor are both a few years old and work fine when they work (i.e., I can use all 4 blower speed settings). I can hear what I take to be a relay clicking when I turn on and off the key. I wonder if there's a relay in there that is going bad...but before I start tearing that apart, is there anything that I should specifically be looking for?

Thanks

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post #2 of 25 Old 10-20-2018, 08:46 AM
shaniqua
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I had this exact same thing happen with my TJ. Sometime the blower motor would work and sometimes not. Of course it was always when you wanted heat that it did not work. I chased down all the possibilities, New resistor, new blower motor, redid the climate control. Turns out it was the ignition switch. I am sorry, I know there is a thread here somewhere but I do not have the link. I turns out that when the ignition gets old, you have to have the key pushed ALL the way in to get the power to the blower motor. Hence the randomness. Jump in turn the key, it starts, but the key is not in far enough to engage the the accessory power.

Change out the ignition switch is not too hard. And that fixed it. Good news is by trying to fix it by going through all the other stuff I have an all new HVAC system.

Hope this helps.
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post #3 of 25 Old 10-21-2018, 06:51 AM Thread Starter
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So to diagnose: play with the key and see if it sends power to the number 8 accessory fuse socket? I had the lock changed out 10 years ago but that is because the key wouldn't turn the Jeep on consistently.

You're right about it being most noticeable when I want heat. Hell, I should just get a shorter belt and bypass the A/C compressor all together!
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post #4 of 25 Old 10-21-2018, 10:54 AM
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I am not sure if checking the accessory fuse socket is correct. I checked it by putting the blower on low and just turning the key and pushing in while I turned it. I probably would have been better if I had used my multimeter, but I was rather frustrated at the time.


All I can tell you is that I went through all of the fixes for the heater. Changed the blower motor, redid the wiring to the heater panel, changed the blower motor relay, changed the resistor and I still had the intermittent problem you describe. As I kept looking I found a thread that mentioned changing the ignition switch because a problem with the actuator pin. As a last ditch attempt, I replaced the actuator pin and it fixed the problem. That being said, it could also be a loose wire or connector in the ignition switch and not the switch itself.


I can't post links yet because I just signed up to the forum, although I have been reading if for a long time.


If you do a search for "heater blower ignition switch" or "ignition switch actuator pin" you will get several links that might help.


I do not want to lead you down a rabbit hole, but when I was dealing with this, after doing all the other fixes found when you do a search for "heater blower not working" it was a relief to find out that it was the ignition switch. I wish I could be more help, but my electrical knowledge is limited.


I hope this helps. Maybe someone with more experience will chime with better advise.
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post #5 of 25 Old 10-21-2018, 11:02 AM Thread Starter
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It does help significantly, thank you. I have a couple multimeters and I was thinking that the fuse socket would only get power if the ignition switch actuator pin (ISAP) was engaged, i.e., the blower should be key activated. So if that isn't the right spot, where would you have tested it with the multimeter? Why doesn't a malfunctioning ISAP prevent other key-activated circuits, e.g., the radio from working as well?

It's like 50F out with 35 mph gusts so I'm hoping to do the diagnosis and repair in a fairly targeted manner so I will look for the other threads to which you referred but any additional help is much appreciated.
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post #6 of 25 Old 10-21-2018, 11:06 AM Thread Starter
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Does this replacement video look right?
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post #7 of 25 Old 10-21-2018, 11:28 AM Thread Starter
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Here're the symptoms. The blower turned on the first time I turned on the key but fails to at 0:15. No amount of moving the key in and out makes it turn on:

https://youtu.be/vkcQZoG4htU


Last edited by iconoclasthero; 10-21-2018 at 12:31 PM.
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post #8 of 25 Old 10-21-2018, 12:27 PM Thread Starter
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There appears to be a bit of carbon buildup on 87 and 87a but otherwise, the relay checks out per

Quote:
RELAY TEST
The blower motor relay (Fig. 16) is located in a wire harness connector that is secured to the heater A/C housing behind the glove box on the passenger side of the vehicle, next to the heater-A/C wire harness connector in the passenger compartment. Remove the relay from its connector to perform the following tests:
(1) A relay in the de-energized position should have continuity between terminals 87A and 30, and no continuity between terminals 87 and 30. If OK, go to Step 2. If not OK, replace the faulty relay.
(2) Resistance between terminals 85 and 86 (electromagnet) should be 75 ± 5 ohms. If OK, go to Step 3. If not OK, replace the faulty relay.
(3) Connect a battery to terminals 85 and 86. There should now be continuity between terminals 30 and 87, and no continuity between terminals 87A and 30. If OK, see the Relay Circuit Test procedure in this group. If not OK, replace the faulty relay.
NB - Test (3) was done with a 9 V battery out of my smoke detector. Results: relay audibly closed, continuity b/w 87 and 30.

So I could clean off the contacts and/or twist them slightly and/or apply a little dielectric grease to them (i.e., with a q-tip).

What, if anything, does the 87a-30 connection do? Could I reasonably swap in a 4-pole relay that I have on hand?
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post #9 of 25 Old 10-21-2018, 04:01 PM
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The best way to test the ignition switch is if 12v power is getting to fuse 8 when you turn the key on. If no either the switch is bad or the actuator is not turning it far enough which is unlikely since normally if the key was not turning the switch to “on” the engine would not run (no power from switch) or there is a broken wire between the switch & fuse panel.

Note that there are about 3 different sets of contacts in the switch which powers various things, each set. So it is possible, & likely, that one bad set will cause loss of power to only some things. Depending on what year you have the ones that power fuse 8 normally also powers fuses 5-7. 5 is the air bag so if the a/b light is on there is a good chance that is dead too. Fuse 7 is for the back up lights so see if they are working.

That relay has been hot so make sure the 87 terminal in the socket is not loose fitting & arcing. 87a is only closed (has continuity) when no power is going to the relay. That is not used for this application, only 87 is used when the blower is on.
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post #10 of 25 Old 10-21-2018, 04:37 PM Thread Starter
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It was a typo...

Quote:
Originally Posted by Rubi4MyMrs View Post
The best way to test the ignition switch is if 12v power is getting to fuse 8 when you turn the key on. If no either the switch is bad or the actuator is not turning it far enough which is unlikely since normally if the key was not turning the switch to “on” the engine would not run (no power from switch) or there is a broken wire between the switch & fuse panel.

Note that there are about 3 different sets of contacts in the switch which powers various things, each set. So it is possible, & likely, that one bad set will cause loss of power to only some things. Depending on what year you have the ones that power fuse 8 normally also powers fuses 5-7. 5 is the air bag so if the a/b light is on there is a good chance that is dead too. Fuse 7 is for the back up lights so see if they are working.
Yeah, that about sums it up. It is a 2003. I was having issues with the B/U lights and the AB dash light started coming on about the same time that the blower stopped working. I had begun to suspect that the latter two were correlated but I hadn't suspected the B/U light as part of it...I was moving fuses around to check the blower and thought that had caused it. I already went ahead and ordered the new switch from Amazon Warehouse:




Quote:
That relay has been hot so make sure the 87 terminal in the socket is not loose fitting & arcing. 87a is only closed (has continuity) when no power is going to the relay. That is not used for this application, only 87 is used when the blower is on.
Ok, it looked like it had carbon deposits on it which is why I posted the pic. I tried to clean off the contacts (scraping, vinegar) and then I put some dielectric grease on it and plugged it back in. How would I check the T87 cavity/socket? Also, both the T87 and T87a contacts had dark residue on them. I think the latter was worse than the former so I think if it was carbonization from arcing, then 87a is carrying current. Further, in the manual, it states that:
Quote:
The relay normally closed terminal cavity (87A) is connected to the blower motor resistor output. When the relay is de-energized, terminal 87A is connected to terminal 30 and provides the blower motor resistor output to the blower motor feed circuit. There should be continuity between this cavity and the blower resistor outputs circuit cavity of the blower motor resistor wire harness connector at all times.
I have read this a few times now and I'm really not sure what it is telling me, but I am sure that spending any further time trying to figure it out isn't going to net me anything in terms of fixing the blower problem. If it illuminates anything as far as the deposits on the relay, I'd like to know...
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post #11 of 25 Old 10-21-2018, 07:30 PM
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The photo is the actuator, not the ignition switch. I think you need the ignition switch. The thing to do is remove your ignition switch from the actuator (one torx t-10 security bolt & it pops off). You will have to remove the plastic covers from around the steering column & may have to loosen & lift the multifunction switch for clearance. There should be videos on u-tube to help. Then with the connector still connected turn the switch from the center slot with a screwdriver. When it is turned to the on position (cluster lights up) see if you have 12v power to any/all fuses 5-8. If not, the switch is probably bad. To check it unplug the switch & from the connector find the pink/black wire (pin 9), 2nd from one corner. That should have 12v. Make a short jumper wire & jump from that terminal over to the black/orange wire next to it (pin 8). That should give you 12v at the fuses (5-8). If it does, you know the switch is bad.

The “deposits” on the relay appear to be from excessive heat usually from arcing (the terminal from connector to relay blade) when it has a load (blower on) which usually happens when the terminal gets too loose maybe from excessive heat. It may be from a simple overload but not likely since normally the wires would show melting before the relay would discolor. Either way, the relay should be replaced. Be sure to carefully check the relay’s connector & wires for any melting or other signs of excessive heat.

Don’t worry about 87a, it is not used & the discoloration on it is probably from the heat from 87.
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post #12 of 25 Old 10-21-2018, 09:08 PM Thread Starter
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It was a typo...

Quote:
Originally Posted by Rubi4MyMrs View Post
The photo is the actuator, not the ignition switch. I think you need the ignition switch. The thing to do is remove your ignition switch from the actuator (one torx t-10 security bolt & it pops off). You will have to remove the plastic covers from around the steering column & may have to loosen & lift the multifunction switch for clearance. There should be videos on u-tube to help. Then with the connector still connected turn the switch from the center slot with a screwdriver. When it is turned to the on position (cluster lights up) see if you have 12v power to any/all fuses 5-8. If not, the switch is probably bad. To check it unplug the switch & from the connector find the pink/black wire (pin 9), 2nd from one corner. That should have 12v. Make a short jumper wire & jump from that terminal over to the black/orange wire next to it (pin 8). That should give you 12v at the fuses (5-8). If it does, you know the switch is bad.
Ok, I'll take a look at that tomorrow. In the meantime, I canceled the ignition switch actuator pin.

Quote:

The “deposits” on the relay appear to be from excessive heat usually from arcing (the terminal from connector to relay blade) when it has a load (blower on) which usually happens when the terminal gets too loose maybe from excessive heat. It may be from a simple overload but not likely since normally the wires would show melting before the relay would discolor. Either way, the relay should be replaced. Be sure to carefully check the relay’s connector & wires for any melting or other signs of excessive heat.

Don’t worry about 87a, it is not used & the discoloration on it is probably from the heat from 87.
So do you know how to get the relay socket off of the HVAC housing? It is in a very awkward spot (and I put my speaker back in already) and I don't want to just rip it off. Maybe one of those prybars for plastic body panel tabs?

I'll take your word for it on 87a. I guess it is never carrying current if the blower doesn't turn on.

Final question: What is the part number for the switch for a 2003 TJ X?
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post #13 of 25 Old 10-22-2018, 11:07 AM
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I can’t help with how to remove the connector.

04793576AB might be the ignition switch but check if it fits your yr.
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post #14 of 25 Old 10-22-2018, 12:19 PM Thread Starter
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Amazon didn't pull up that 04793576AB but when I jumped off of that ISAP order I canceled, it came up with
http://a.co/d/hfF7xkJ
and
http://a.co/d/dJBIb9t

Amazon said both fit my 2003 X and the latter, the Doorman part, is listed as correct for both the 4- and 6-cylinder 2003 Jeeps.

Is this the part you think I need? I'm off to get the security torx set from THD so I'll pull it apart today or tomorrow.
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post #15 of 25 Old 10-22-2018, 12:22 PM Thread Starter
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FWIW, this is in stock at my local Advanced Auto Parts store for a couple dollars more than the Doorman is at Amazon:

BWD Ignition Starter Switch
LIMITED LIFETIME REPLACEMENT
Part # CS812 Price: $18
Exact Fit for your 2003 Jeep Wrangler X

Ignition Starter Switch
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