I have 92 ply Voyager turns over fine

Do you mean no 12 volts at the ignition coil or injectors during cranking or for the first one second after turning on the ignition switch? If that is correct, swap the automatic shutdown (ASD) relay with another relay like it such as the AC compressor relay, then see if you get voltage on that circuit. If not, remove the relay and check for voltage on terminal 30 or 87. Sorry, I can't remember which one but one of them must have 12 volts all the time. If neither has it, a fuse is blown. If you do find it, feel if it is clicking when a helper turns on the ignition switch.

The web site changed last week to a new format and the site host is having a huge problem with sending out automated e-mails letting you and me know when a reply is posted. What I've been doing is right-clicking then opening each new question I read in a new tab, then I leave those tabs open so I can refresh them later to see if a reply was posted. Unfortunately I have well over 100 tabs open and it has slowed my really old computer to a crawl. If it went any slower it would be going backward! It is common to take 5 - 10 minutes to switch to a new page.

Don't start a new question as that will just make it worse. I started getting a few automated e-mails this afternoon. I noticed both of yours came through. On the site they are listed as you replied last night, but I just got the message at 1:12 p.M. Today. Hopefully this will be fixed soon, then I may get flooded with hundreds of replies to answer. Sleep is over-rated anyhow.

As for your ASD relay, the 12 volts on terminal 30 is correct. That is the feed for the switched current to the injectors, coil pack, fuel pump, alternator field, and oxygen sensor heater. The 12 volts from the ignition switch to terminal 86 is also correct. That feeds the coil inside the relay. Terminal 87 does indeed need to be grounded but that is done by the Engine Computer. You can't measure that circuit for continuity. All you can do is watch its operation for that first one-second blip when you turn on the ignition switch. The easiest way to do that is to monitor the voltage we've been talking about from relay terminal 87 which goes to the injector, coil, etc. The second way is to feel if the relay clicks on, then clicks off one second later when a helper turns the ignition switch on. The third way, which is more time-consuming, is to place the probe of your test light on terminal 85 while the relay is installed, AND since you're testing for a ground, you have to move the test light's ground clip to the battery positive post. This way the test light will light up at the same time the relay is energized.

If any of those methods proves the relay is turning on for one second, that proves the circuitry is good and the computer has control of the relay. If the switched 12 volts shows up on 87 it should also be showing up at the coil and injectors. If it's at 87 but nowhere else, there has to be a break in that wire or a corroded splice.

Once you verify the 12 volts is showing up at the coil and injectors for one second, the next thing is it has to reappear during engine rotation, (cranking or running). If it does not, the computer isn't grounding the ASD relay terminal 85 because it doesn't know the engine is rotating. That is because a signal is missing from the cam or crank sensor or both. A scanner that displays live data will show both of them as "no" or "present" during cranking so you know which one to diagnose. If one signal is missing, suspect the sensor, its air gap, or a break in its signal wire. If both signals are missing, suspect a break in the 5, 8, or 10 volt wire that feeds both of them, a break in their common ground return wire, or the feed wire is shorted to ground by a pinched wire or shorted sensor. That feed voltage should be present all the time the ignition switch is on. If you don't find it at either sensor, unplug them and measure on the plugs after turning the ignition switch off and back on. If the wire or either sensor grounded out that feed line, the computer shuts that power supply down to protect it. Once the short is removed, you have to cycle the ignition switch off and back on to reset it. Missing the supply voltage to the sensors is not very common so we'll address that later if it becomes necessary.

Just for information purposes, you need 12 volts from the ignition switch to relay terminal 86 AND the ground on 85 to energize the coil inside the ASD relay. That is a double safety circuit and is extremely reliable and effective. In a crash that ruptures a fuel line, the engine can't run without fuel pressure so it stalls. That means no pulses from those two sensors so the computer turns the ASD relay off. That removes the 12 volts going to the fuel pump, or, on some models it also turns off a separate fuel pump relay along with the ASD relay. Either way the pump stops dumping raw fuel onto the ground where it would be a fire hazard. That wire between the computer and terminal 85 is only a few inches long but if it somehow got pinched or someone tried to modify it, the relay would still get turned off by turning off the ignition switch.

Unfortunately there is no easy way to know if the pulses are being received by the computer except with a scanner.

If you do find steady voltage at the coil and injectors during cranking, that indicates you have a less-common problem with one of the three individual circuits, the ignition coil, injector circuit, or the fuel pump. Of the three a dead fuel pump is the most likely suspect. You won't hear it hum for that one second after turning on the ignition switch. The coil pack would be next. You would have no spark but you would have good fuel pressure and you'd smell the raw fuel. If all the injectors were dead, suspect a break in the common wire feeding them from the ASD relay. Failure of one driver circuit in the computer is rare, and a total failure of all four, six, eight, or ten is unheard of. More commonly that would be caused by a blown fuse feeding the computer.

There are multiple 12 volt feeds for every computer. Pin 9 is the 12 volts from the ignition switch "run" position. That circuit taps off and goes to fuse 14, a 2 amp, for the cruise control. That all comes off the ignition switch which is fed through an orange fuse link wire by the left strut tower. Pin 3 has 12 volts all the time. That circuit is tied in with the feed for the ASD relay, (16 gauge red / white wire). If that's missing, there's a 22 gauge white fuse link wire by the left strut tower. The other side of the ASD relay feeds the injectors and coil(s), and it goes to pin 57. That tells the computer it was successful in turning that relay on. Looks like those terminals are the same for all three engines.

Fuse 3, a 20 amp, feeds the power mirrors and radio memory circuit. That should be live all the time. If that fuse blows, suspect frayed wires between the driver's door hinges. Fuse 6, a 10 amp, is the switched 12 volts for the radio.

For the overhead unit it would be easier if you tell me what's not working. There's so many circuits feeding it for all the different lamps and rear vent windows that it's hard to follow. I see a 30 amp circuit breaker in cavity 25 but it just shows it going to a connector but it doesn't say for what.

If the display is dead, that would mean a 12 volt feed or a ground is missing, but I can't find anything that would cause that if the lights are working. The only switched circuit is the tan wire but that has to be okay because it's the feed for the power vent windows.

You can also look at the two data buss wires. Those are the violet / brown and white / black next to each other in the connector. Those aren't needed for the lights and vent window motors but they might be what tells the display to turn on. The data buss signals come from the Body Computer.

If you have dashes in the display, the unit is working but that indicates a problem with the sensor. That should only affect the outside thermometer though. If the sensor is unplugged, the display should say "OC" for "open circuit".

For the speedometer, look at the speed sensor in the tail housing of the transmission. Look for stretched terminals in the connector although that will usually cause intermittent operation at any speed, not at a specific speed all the time like you indicated. Look at the plastic gear on the end of the sensor, (if that's the design they're still using), to be sure no teeth are worn down. A more likely cause would be the sensor itself has a partially-shorted coil of wire inside and must be replaced. Signals generated this way are a result of the strength of a magnetic field, the size of the coil of wire the voltage is induced into, and the speed of movement between those two. If the coil of wire becomes smaller, as in when it's partially-shorted, you'll need more speed to overcome the weaker signal that is induced into it.

The red brake warning light is due to low brake fluid level in the reservoir, the parking brake pedal isn't fully released, or there was unequal pressures in the two hydraulic circuits. First pull up on the parking brake pedal. If the light goes out the cable is stretched, misadjusted, or more commonly a cable by either rear wheel is sticking partially-applied. The switch on the parking brake pedal could be damaged too. Don't waste your time trying to bend them straight. Find a good used one in the salvage yard.

Unplug the level sensor on the side of the master cylinder reservoir. If the light goes out and the fluid level is okay, the float has sunk or the switch is shorted. If the level is low there is either a leak that must be addressed, the front pads are worn, but you said they're new, or the fellow didn't fill the reservoir after bleeding the system.

Unplug the wire from the combination valve on the frame, under the master cylinder. If the light goes out, the valve has tripped from unequal pressures. That can happen during improper bleeding procedures or when a leak was in one of the systems. That valve is spring-loaded but it often gets stuck. Once the condition that caused the valve to trip is fixed, it is sometimes necessary to jar it loose with a few hard, quick jabs on the brake pedal.

Don't worry about the yellow ABS warning light yet until the red one is solved. It will be on because the ABS Computer can't guarantee proper operation when there's some other problem with the base brake system pressures. Once the red one is off, you'll have to turn the ignition switch off and back on to reset the yellow one. If the yellow one stays on by itself after the red one is off, a problem has been detected and reading the stored diagnostic fault code will get you into the circuit or system that needs further diagnosis.

The transmission fluid is typically supposed to be changed every 36,000 miles. Mine on my '88 Grand Caravan has been changed once in 237,000 miles, at around 90,000 miles, and I use it to regularly drag around a tandem axle enclosed trailer that's bigger than the van. That is no longer neglect. That's abuse, and I don't recommend that to anyone.

I messed up with that gear. I was thinking of a rear-wheel-drive van I had replied to earlier. With the 4-speed, you have an input speed sensor and an output speed sensor. The Transmission Computer calculates road speed by the programmed-in tire size and axle ratio. It sends that information to the Body Computer which interprets it and sends it to the instrument cluster.

Don't even think about switching to a different model transmission. We run into enough trouble with the same model from different years. The computers will be different among many other things. Beginning on various models in the early 2000s all car manufacturers switched to the new "CAN Buss" system. That's a different type of computer signal and is not at all compatible with older computers. The Transmission Computer is needed for the transmission it's designed for, then you'll need the newer Body Computer which tells all the other computers when to turn on. You'll need the newer versions of every single other computer including the instrument cluster, (which won't fit), Air Bag Computer, and Anti-lock Brake Computer if you have one. All the connectors will be different so you'll be cobbling all new wiring harnesses.

The mounts are going to be different too to match the newer body designs.

There's two speed sensors on the four-speed transmission. If either one doesn't produce its signal, the Transmission Computer will default it to second gear. If your is shifting properly, the sensors are working. That means the Body Computer or the Transmission Computer aren't sending the speed information out on the "data buss". That's the pair of wires all the computers share information on. There could be a problem on the instrument cluster too but that's not real common.

You'll need a scanner to see what's going on. It will display the road speed the various computers are seeing. If that is correct, the problem is in the cluster. Most scanners can also run a gauge test. That will run them all up to 1/4, 1/2, 3/4, and full scale. That will show if the gauge is working.

Can't help you with the newer cars and transmissions. I DID recently find out that you can replace the 2.7L in an early 2000s Intrepid with a 3.5L, and use the same transmission AND the same Engine Computer. One of the reasons I became a Chrysler fan in the 70s was they built in so much parts interchangeability among many models and years but I never would have believed two different engines would run perfectly on the same computer.

For your overhead unit, the sensor is inside it for the compass. It consists of some "Hall Effect" transistors which are controlled by a magnetic field instead of a small current flow like normal. Turning those transistors in the earth's magnetic field causes them to conduct more or less, then the computer circuit looks at which ones are conducting the most current to figure out how they're oriented.

The sensor for the thermometer sits on the middle of the brace in front of the radiator. It has two wires, and the sensing element on the other end is a round cylinder about 3/8" long and 1/4" in diameter. Because it sits so close to the radiator and would be affected by its heat, that reading will not update or change while the van is standing still. It needs road speed and air flow to be accurate.

I don't know what the second sensor is for. There is no separate sensor for the radiator fan. There are two coolant temperature sensors on the engine near the thermostat housing. One is for the dash gauge and will always have one wire, usually purple. If you unplug it the gauge will go to "cold". If you ground the wire, the gauge will read full "hot".

The coolant temperature sensor for the Engine Computer will always have two wires. If you unplug that one with the ignition switch turned on, the reading on a scanner would be -40 degrees, and the radiator fan will turn on because the computer knows that is not a valid reading and it doesn't know if the engine is overheating. Just in case, they turn on the fan. That will also turn on the Check Engine light and set a fault code in memory for "Coolant temperature sensor voltage too high". The fan will go off when you reconnect that sensor, and on some models the Check Engine light will go off. If the light stays on, it will be off the next time you start the engine. The fault code will erase by itself after 50 starts.

When the Engine Computer sees approximately 210 degrees from the coolant temperature sensor, it turns on the radiator fan relay. It turns it off at 198 degrees.

The evaporative emissions system including the gas tank is pumped up to 2 psi so you won't hear a leak. A big leak is generally the gas cap was left loose but also look for a hose disconnected between the tank and the charcoal canister.

When you can't find the cause visually, you need a smoke machine to inject a white non-toxic smoke into the system, then you look for where it sneaks out. You might find one at an auto parts store that rents or borrows tools.