'94 Acclaim - No Headlights in Cold Weather

The headlights on my '94 Plymouth Acclaim won't work when the outside temperature is below freezing. But they do work when the temperature rises above freezing. All the other lights and electrical components work fine regardless of the temperature. Any suggestions appreciated.

Gary

Reply to
Gary Kaucher
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US model (no Daytime Running Lights) or Canadian model (with Daytime Running Lights)?

Probably a bad headlamp switch, which is not at all difficult to change with simple hand tools. If a Canadian model, the DRL module is a suspect in this fault, as well.

Reply to
Daniel J. Stern

It's a US model with no Daytime Running Lights. In the last 2 months the car has been giving me a number of electrical problems that usually resulted in a fault code 41 ( Alternator field control circuit open or shorted). My mechanic noticed that a ground strap had deteriorated and fallen off, so he fixed that. He first replaced the alternator & a headlamp relay, but it wasn't until he later replaced the PCM with a used PCM that the fault code

41 went away and has not returned.

Is a headlamp switch the same thing as a headlamp relay?

Gary

Reply to
Gary Kaucher

About 2 months ago I was getting fault code 41 (Alternator field control circuit open or shorted) a lot. My mechanic first replaced a deteriorated ground strap, the alternator, and a headlamp relay. It wasn't until he later replaced the PCM with a used PCM that the fault code 41 went away for good.

Is a headlamp switch the same thing as a headlamp relay?

Gary

Reply to
Gary Kaucher

That's a good question. A relay is a switch but a special kind of switch, looking this up on the internet quickly for you. I just punched into Google "relay switch." Let me take a guess on this. A headlamp circuit is probably the highest or one of the highest current draws in a vehicle. The current could go directly through an ordinary switch or it could go through a relay-switch. A relay then relays the current - make sense? This might be equivalent to a transistor controlling an awful lot of current. But in this case it's mechanical instead of electronic or transistorized. Is that about right? Or are there switches AND relays in this case? I don't know - would have to see a wiring diagram for the vehicle since I have replaced one headlight switch but not a relay yet.

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"A relay is an electrically operated switch. Current flowing through the coil of the relay creates a magnetic field which attracts a lever and changes the switch contacts. The coil current can be on or off so relays have two switch positions and they are double throw (changeover) switches."

"Relays allow one circuit to switch a second circuit which can be completely separate from the first. For example a low voltage battery circuit can use a relay to switch a 230V AC mains circuit. There is no electrical connection inside the relay between the two circuits, the link is magnetic and mechanical."

"The coil of a relay passes a relatively large current, typically 30mA for a 12V relay, but it can be as much as 100mA for relays designed to operate from lower voltages. Most ICs (chips) cannot provide this current and a transistor is usually used to amplify the small IC current to the larger value required for the relay coil. The maximum output current for the popular 555 timer IC is 200mA so these devices can supply relay coils directly without amplification."

"Relays are usuallly SPDT or DPDT but they can have many more sets of switch contacts, for example relays with 4 sets of changeover contacts are readily available. For further information about switch contacts and the terms used to describe them please see the page on switches."

Reply to
treeline12345

deteriorated

With a 1994 Plymouth Acclaim does a low voltage headlamp switch control the high voltage headlamp relay? If so, is the headlamp switch or headlamp relay more likely to fail when it is cold (or moist). The headlights never fail when I want them to. Is there someway to test this besides asking my wife to go pick up groceries at night when the temperature is dropping, and waiting for the distress phone call?

Gary

Reply to
Gary Kaucher

You mean "low current" and "high current", not "low voltage" and "high voltage", and no, there is no relay in the headlamp system of a '94 Acclaim.

I'm not sure you'd ever really *want* the headlamps to fail. Do they ever start out working, then fail? Or is it strictly a situation where you cannot rely on them coming on when you pull the switch?

There is, now that I think of it, another failure point equally likely as the headlamp switch to cause this problem. That is the beam selector switch, properly "multifunction switch" which controls the headlamp beam, turn signals, wipers and hazard flashers. When the headlamps will not turn on, what happens if you pull the turn signal lever towards you? Not far enough to cause it to click, as though changing beams, but just shy of that point? Any response from the headlamps?

DS

Reply to
Daniel J. Stern

Good...checking and repairing grounds is always wise. Note that these cars have VERY thin headlamp ground wires, 18 or 20 gauge, which connect to sheetmetal (body) grounds. It's entirely possible your sporadic headlamp operability is due to an intermittent ground. Do you own a voltmeter? Know how to use it?

I don't know what he thinks he replaced (or what you think he replaced) but it was not a headlamp relay, unless relays were added to the headlamp circuit by you or a previous owner. Acclaims don't have headlamp relays from the factory. The headlamp circuit is the typical simple type found on many US cars for many decades: Power via a fuse to the headlamp switch, from the headlamp switch to the beam-selector switch, from the beam selector switch directly out to the headlamps. Looks like this, schematically:

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These computers ("PCM" or properly SBEC) seldom fail, but on the occasion they do fail, the voltage regulation function is usually what fails.

No. Your car *does* have a headlamp switch. It does *not* have a headlamp relay, unless one was added.

Reply to
Daniel J. Stern

Reply to
Daniel J. Stern

I will see if I can find the ground wires. I have a voltmeter. I suppose I would be testing for continuity on bad wires. The car is not garaged, so corrosion and wear is quite possible.

The bill from the mechanic says "headlamp relay", but maybe he meant "headlamp switch". I did see something about headlamp relays at

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for the 1994 Plymouth Acclaim (both 2.5L and 3.0Lengines). I have the 3.0L. Another possibility is that he replaced acompletely different relay. I think there is one between the coil and thePCM that causes electrical problems. I will find out.Thanks for your insight.

Reply to
Gary Kaucher

Until all these electrical problems go away for a few months I won't feel that I can relay on the lights. I was hoping to prove that some component is causing the headlights to fail when the temperature is cold or the weather is wet. I suspect that the problem would be easier to diagnose if the lights would just stop working all the time instead of intermittently.

I will try that out the next time that the lights fail. "Hopefully" that will be tomorrow morning when the temperature falls to 10 degrees. Thanks for suggestion.

Reply to
Gary Kaucher

They are the leftmost wires leading into the headlamp sockets (rightmost socket slot if you remove the socket and look into it)

Well, when the headlamps fail to turn on, leave the switch in the "on" position, put your voltmeter's negative probe onto a good ground (e.g. battery negative) and probe the middle and left socket slots (removed from bulb) looking for ~12v. If you don't see it, your headlamp and/or beam selector switch(es) is/are faulty, or there's a fault in the wiring between them and the lamps.

Shows two items: The first listing is for rear defogger and A/C applications in the AA-bodies (Spirit, Acclaim, LeBaron sedan). It is used for headlamp duty in certain other '94 Chrysler products. The second listing (the round item) is the under-dash thermal timer that controls the "halo" light around the ignition switch.

That would be the ASD relay -- nothing to do with the headlamps.

DS

Reply to
Daniel J. Stern

Yesterday morning, the outside temperature went down to 7 degrees Fahrenheit. Despite this, the headlights worked fine. It didn't go above freezing all day, and this morning it was 4 degrees Fahrenheit and the headlamps won't work at all. The parking lights come on, but no headlights, high or low. I found my old voltmeter and confirmed that it worked (12 volts across the battery terminals - no problem). I turned on the beam selector switch and removed the plug from behind each bulb and probed the sockets, using the negative battery terminal as a ground. In all cases, I get no needle deflection.

I don't see any noticeable wire damage or disruption in the immediate area of the headlamps. I will find out if my mechanic already changed the headlamp switch and incorrectly called it a "headlamp relay". If so, then maybe the beam selector switch is the problem.

I also tried your suggestion of pulling back on the turn signal with the beam selector switch turned on, and the headlights still didn't turn on.

Reply to
Gary Kaucher

headlights,

I spoke to my mechanic. He said that he had previously replaced a headlamp relay, not the headlamp switch. The headlamp relay that he replaced apparently has something to do with the low beams, but it is quite possible that he replaced that relay for reasons unrelated to headlights. That was when he fixed the problems that gave me the 41 fault code.

I really think (hope) that problem is gone and that this problem might just be the headlight switch. Is there some way I can use my voltmeter to determine if it is the headlight switch or beam selector switch? Thanks for your help in understanding this.

Reply to
Gary Kaucher

You need to locate the relay and see if it clicks every time the headlight switch is turned on. If it doesn't click, then you need to probe the socket with your meter or preferably just swap it with another relay. The relays will interchange if the numbers on the pins are the same.

The power you would be looking for with the switch on would be on pin 86 if it is a standard Bosch style relay. With the headlight switch off, the power to pin 86 will be off. You can put the meter in pinhole 85 and 86 and when the switch is on, you should see 12 volts there.

A dirty or rusty connection on the relay will cause your symptoms.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's Canadian Off Road Trips Photos: Non members can still view! Aug./05
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Reply to
Mike Romain

OK, that's good info.

OK, more good info.

There is STILL no headlamp relay in a 1994 Acclaim, as delivered from the factory. Here are the wiring diagrams:

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The first diagram shows the headlamp switch and all its connections.

The second diagram shows the multifunction switch (beam selector, turn signal, windshield wiper) and all its connections.

The third and fourth diagrams show the left and right headlamps and their connections.

There is no relay present in any of these diagrams, just as there is no headlamp relay present on the vehicle unless somebody added one sometime in the past.

Just right off the bat, we can eliminate certain problems. Note that the headlamp switch's main feed is wire number A3, a 12ga red-and-white wire. We know power's coming in on this wire and reaching the switch, for the headlamps *sometimes* work, and even when they don't, the parking lamps carry on working. Since the headlamp switch gets power to send to the parking lamps from A3, we know this isn't the failure point.

Next wire to focus on is wire number L2, a 16ga light green wire that goes from the headlamp switch to the multifunction switch. When the headlamps refuse to work, if this wire meters out at 12v relative to good ground with the headlamp switch on, then the headlamp switch is not the problem. If this wire shows no voltage under those conditions, the headlamp switch is faulty.

Next wire to focus on is wire number L4, a 16ga purple/white wire connected to the multifunction switch. When the headlamps refuse to work, if this wire meters out at 12v relative to good ground with the headlamp switch on, alternating on and off when you click the lever back and forth between low and high beam positions, then the multifunction switch is not the problem. If this wire shows no voltage under those conditions, then the multifunction switch is faulty.

Next item down the line is fuses numbered 3 and 4, which respectively feed the left and right low beams. It would be most unusual to find a problem here.

Headlamp relays have one function: To control the headlamps. Your car didn't have a headlamp relay from the factory, so unless someone added one at some point in the past, your mechanic doesn't know what the hell he's talking about. The only relay in the lighting system of a '94 Acclaim would be a fog lamp relay, if your '94 is one of the very few that came with fog lamps. The fog lamp relay's failure would not prevent the headlamps working.

I really think it is either the headlamp switch or the multifunction switch.

See above.

Reply to
Daniel J. Stern

This is the best display of diagrams I have seen. You set this up as a toggle between regular size and a big, expanded size of the diagram. I just click the mouse and it toggles regular and large size. It would be nice if this is a new trend for showing diagrams over the internet rather than separate frames. I had not noticed this before anywhere else. This is the quickest way and easiest to follow tracing a circuit by zooming in and out.

Reply to
treeline12345

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Thanks for the drawings and explanations. I am a novice, but now I understand what I have to look for, and I may have a good opportunity to check this out soon. The morning temperatures here in Pennsylvania have been in the single digits lately, and my headlights only come on in the afternoon.

Is there an easy way to access the headlamp switch? To take readings do I remove the switch and probe sockets or do I probe through the insulation into the wire?

Is there an easy way to access the multifunction switch? Is it located somewhere on the steering column?

Reply to
Gary Kaucher

I find myself wondering what happens if you start the car when cold, turn the headlamps on (and they don't come on), turn the heater on full blast and wait. Will the headlamps come on at some point?

NEVER probe through the insulation!

To remove the headlamp switch:

-Remove the main dashboard trim panel surrounding the instrument cluster and containing the two centre dash vents. This whole trim piece simply pulls off; get your fingers under the inner edges adjacent to the instrument cluster and pry it rearward until one or two of the clips disengage, then move around the trim piece pulling carefully but firmly rearward, and eventually the piece will pop free. Lift it away from the dash and put it in the back seat.

-Remove the trim panel surrounding the headlamp switch. This, too, simply pulls off.

-Remove the philips head screws holding the black plastic headlamp switch panel to the dashboard. The panel and switch assembly can then be pulled away from the dash. At this point you should be able to access the wires plugged into the headlamp switch. You can 'backprobe' them (insert voltmeter probe alongside the wire of interest, into its plug cavity, making contact with its terminal without damaging the insulation).

If you need to replace the headlamp switch, carry on as follows:

-Disconnect the battery negative cable from the battery.

-Find the small round-headed, spring-loaded pushbutton on the side or bottom of the headlamp switch. Press and hold it in towards the headlamp switch firmly (it helps to tape a coin to your finger or thumb). While holding it in, firmly pull the headlamp knob until it disengages from the switch and pulls free. Set it aside.

-Remove the headlamp switch from the switch panel.

Installation is the reverse of removal.

It's not difficult, but you will need one special tool: A tamperproof Torx driver (or tamperproof Torx driver bit). Size is either T15 or T20. A regular Torx won't fit; it must be the tamperproof type which has a hole in the centre of the driver or bit.

-Using the tamperproof Torx driver, remove the single screw located in the middle of the bottom of the steering column cover.

-Using a conventional driver, remove the two or four fasteners located at the corners of the bottom of the steering column cover.

-Grasp the bottom half of the steering column cover and pull it off of the column if it does not drop off on its own. Set it aside.

-If the car is equipped with tilt steering wheel, grasp the tilt release lever shaft carefully with pliers and unscrew it. Remove and set aside.

-Lift the top half of the steering column cover off and set it aside.

The multifunction switch is now exposed. Two screws hold it to the steering column, and one screw secures its wiring plug.

Installation is the reverse of removal.

DS

Reply to
Daniel J. Stern

I hope you are joking and if you aren't the image zooming is a "feature" built into internet explorer 6 whenever you load an image file that isn't embedded into a web page. It shows up as a button in the lower right hand corner of the image when you hover the mouse pointer over the image. To turn it off you go to: Tools Menu>Internet Options>Advanced tab>scroll down and "Enable Automatic Image Resizing" will be the first thing listed under "Multimedia"

Reply to
Daniel Armstrong

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