TR4/4A TR4 HAS NO POWER, WHAT TO CHECK?

[TR4]

MY TR4 RECENTLY LOST ELECTRICAL POWER AND AT FIRST, I THOUGHT IT WAS THE IGNITION SWITCH BECAUSE I ONLY HAD POWER IN THE ACCESSORY POSITION BUT THE SWITCH PROVED TO BE IN GOOD CONDITION THROUGH BENCH TESTING. I TESTED THE COIL WIRE, SOLENOID WIRE AND FUSE WIRE TO MAKE SURE ONE DIDN'T BREAK AND THOSE ARE GOOD. FUSES ARE GOOD. WHAT WOULD BE NEXT TO CHECK, THE VOLTAGE STABALIZER? DOES THAT HAVE ANYTHING TO DO WITH LOST ELECTRICAL POWER? HOW DO I TEST MY UNIT? ALL ADVICE IS GREATLY APPRECIATED.

 

[Geo Hahn]

I do not understand where you do and do not have power. For example, with the ignition switch in the 'on' position do you have power at the white wire on the coil? Do you have power at the back of the ammeter (either post)? Do you have power at the green wire from the ignition switch?

The voltage stabilzer would affect the fuel gauge & temp gauge... but not much else I can think of.

If you have nada power anywhere and the battery is good then I would start by confirming the ground connection (battery to firewall) is good.

 

[Andrew Mace]

How are the "major" battery and ground connections? A failure of the voltage stabilizer would, I think, only affect the fuel and temperature gauges.

What about the ammeter? If that fried, it pretty much cuts power to everything as well.

Also, fuses may look ok but still have enough corrosion on the ends (or on the fuse box terminals) to kill power. Sometimes just moving them back and forth will be enough to restore. But that shouldn't affect the ignition circuit.

 

[TR4]

When I say no power, there is no power when the ignition switch is on or when switched to the start position. No guages seem to have power and the radio did not work but when I switched to the accessory position, the radio worked. I checked to see if there was power going to the starter and there is not. If the ammeter is fried, could I bypass that to test the system? Also, can I test the system by using a tester on the wires to the ignition switch since I currently have that removed? Which two could I connect the tester to?

 

[martx-5]

Using these wiring diagrams from Dan Masters site, just get a voltmeter and start at the battery and work your way along until you find out where the electricity gets lost.

I have a gut feeling that your battery is dead.

 

[Adrio]

in responce to your two question:
1) yes you can bypass the ammeter with a thick wire that can handle the full current of the system.
2) yes you can test the ignition switch with a meter. Just set it to resistance (ohms) and see if there is continuity (low resistance or zero) between the appropriate two terminals for each position switch. Also check that there is no continuity between the terminals that are suppose to be open.

 

[Harry_Ward]

/ubbthreads/images/graemlins/iagree.gif Or the + ground wire is not connected or has come loose. Then check the path from one component to the next using the wire diagram. EDITED - Opps didn't remember the part about the radio. See below

 

[danmas]

if you are geting power to the radio when the key is in the ACC position, you need to look no further for your troubles - you have a bad switch. Or, you have more than one wire loose/bad connection at the switch.

If your ammeter were fried, you wouldn't get power to anything except possibly your horns.

 

[TR4]

Latest update, the battery is ok, ignition switch is ok and there is power going to the solenoid when I hit the switch. If the solenoid has lost it's ground, can I run a ground wire from the negative post on the solenoid to the negative post on the battery to test the solenoid? If nothing then, I guess I could bypass the solenoid by connecting the posts with an insulated screwdriver to test the starter. I still do not have lights or radio so the problem is not likely the solenoid or starter but that is where I thought I would start eliminating probable causes.

 

[martx-5]

First of all, TR4's originally came with a positive ground setup. TR4A's had negative ground. Your TR4 may have been changed. Where is the Positive cable from the battery going?? To chassis ground, or the solenoid?? If the positive is going to chassis, then it's positive ground.

Either way, that solenoid is grounded through it's casing to the body. The current from the start switch goes to the small connector on the solenoid, through the coil inside and then to ground though the case. You said you've got juice to that connector. If the coil is good, you should here it click when you try to start the car. If it doesn't click, then the coil is most likely bad, or the ground between the casing and the body is bad. If you want to check to see if the starter spins, then yes, you can jump across the two large terminals to see if the starter spins. Just be careful, that starter draws a couple of hundred amps. There will be a lot of sparking.

Also, since you don't have juice for other parts of the car, check the connector on the solenoid where it comes in from the battery. There should be some other wires attached there that feed the rest of the car. If you have a lousey connection there, it may explain all your problems.

Edit: Doesn't your solenoid have a push button on it?? If so, just push it and the starter should crank over. No need for jumping across the large studs.

 

[MDCanaday]

This is where a lot of LBC owners go wrong (IMHO) If you have a system that has old car troubles dont try to find the one spot that has failed now, go through the entire system and freshen up all the connectors,grounds and fuses. You would be very surprised at how many fuse blocks look Ok but are NOT.How much does a set of new plug-in connectors cost really??.Not much if it adds years of trouble free driving.Clean each bullet wire end and lube lightly as you put on the new connectors,get NEW battery cables and ground strap for the engine. If you take the time to do it RIGHT, you will only have to do it ONCE!!!!
MD(mad dog)