m35a3 wont start

[Coalman]

I have a m35a3 and it wont turn over all it does is make a clicking sould at the firewall. I checcked the voltage and it is reading 23 volts at the starter . so I guess that rules out batteries. I did check the voltage at the solanoid on the firewall and it reads 23 volts on the one side and 9-11 on the other side when you hit the starter switch . How do I test the switch to make sure, and also could it be the starter ??? I tried bypassing the solanoid and nothing happens. I did take the solanoid out and was planning on replacing it first but they run over $100 bucks. So I was hoping to make sure what I needed rather than just putting parts on and guessing Thanks in advance

 

[glcaines]

Turn on the headlights. Are they bright? This is a qucik and dirty method of checking batteries. Start with the simple things first. Don't assume you have a bad relay or solenoid. I would remove all battery cables and clean the terminals. Charge the batteries. If you don't have a 24 V charger, simply charge each battery separately. With the batteries fully charged and clean battery cable terminals, try to start it again. If you still get the same thing, check the ground cable connections. Then check the positive cable connections at the relay/solenoid. If the starter still won't turn over, you will have eliminated a lot of possibilities and it is always good PM to clean the cable connections anyway. If it still won't start it is likley the relay/solenoid.

 

[Coalman]

I did check all the wires The problem is the truck is about 20 miles from home in a parking lot. I do have 23 volts at the starter so I don't think it is batteries Is ther any way to test the relay (mounted on firewall) I did bring it home with me also how do I check if it is starter?? Thanks

 

[rickf]

I am not real familiar with this truck but how do you have 23 volts at the starter but only 12 at the relay? Does it not go through the relay to the starter or is it a low currant relay to a second high currant relay on the starter? No matter, a 12 volt drop under load would indicate to me a dead battery. It may show voltage at rest but dead under load. Like was mentioned, turn on the lights and hit the switch, do the lights go out? 23 volts at rest is too low anyway, should be close to 25 for fully charged batteries.

Rick

 

[tomcata3]

Sounds like you need a relay, you are not going to find one in a local store.
I have a new one that i can sell you for $120 if you want to drive over and pick it up

 

[Coalman]

What I did was checked the voltage going in the relay and then with someone holding the switch on and the switched side was only 9-11 volts I took the relay apart and it did smell burnt I just don't want to go and buy a relay and than it be the starter Will any 24 volt relay work? it looks very simple inside .

 

[Coalman]

One other thing that has me confused is, I tried to bypass the solenoid on the firewall and nothing happened it just sparked Shouldn't the starter engaged ?

 

[rickf]

You need to check the battery voltage while someone hits the switch. If the voltage does not drop there then the relay is bad. 23 volts is still too low and will cause an increase in amperage across the relay. It may not be enough to burn it but do not hold it to long if it does not start. You should be able to bypass the relay to start the truck.

Rick

 

[Coalman]

Ok I did not get to check the voltage at the batteries while the starter was hit. I do know that when I hit the starter switch that all the gauges drop. I was just assuming that the switch was only putting out 9-11 volts Maybe the batteries where just dropping It will be a day or two till I can check The truck is 20 miles from home and I have a lot to do this weekend I guess I could take two good batteries from one of my dozers and put them in Thanks Kevin

 

[Coalman]

Also even if the voltage is real low shouldn't it atlest try to crank? Sorry for all the dump questions but this just has me thinking Thanks

 

[tuckered]

Let us know what the problem was, when ya find out. Thanks.

 

[rickf]

Anything below 23 volts and I doubt you will get much of anything. I would say if you are driving 20 miles then take two good batteries with you. Check the ones in there first like I said, have someone hit the switch while you have a meter on them. What does the voltmeter in the truck say? If that is dropping then the batteries are toast. The relay creates an arc every time it closes so it will smell a little burnt normally. If the batteries are bad replace them first and try it. Like I said, I am not familiar with that particular truck but vehicle electrics are all the same principle.

Rick

 

[tuckered]

Oh yeah, Just a thought. . .

To get it home, have you considered 'poping' the clutch. avoids so many trips. just a thought.

 

[Coalman]

It is an automatic Wish it was that easy. I did clean the relay contacts before putting it back together. Will a battery drop do that quick and come back as soon as load is taken away? I alway thought once it dropped it wouln't come back that fast .Well I guess i will have to wait till monday to find out Thanks so much for all the input

 

[Sephirothq]

if you need that bar you will have to pick it up tomorrow as i am out during the week.

 

[rickf]

One dead cell in the battery will do exactly that. Have you checked the acid levels lately? How old are the batteries? If they are more than 4 years old then replace them.

Rick

 

[glcaines]

I think you have dead batteries. It could be bad batteries, bad alternator, etc. If you have jumper cables, charge the batteries one at a time with your car using jumper cables. Before charging, check the electrolyte level as rickf suggested above. Make sure you use distilled water to bring up to the ring in the cells if needed. Once you get it started make sure the needle is on the tick mark on the meter.

 

[Rustygears]

Ditto to the above post.

You could also try jumping it through the NATO connector on the pax side of the cab if you have either a friend with an mv or a couple of batteries. I'd disconnect the existing truck batteries first. If the alternator is good, once the truck is started you can limp home without any batteries.

 

[ehinlein]

I had exactly the same thing happen with my A3 a week ago. They were '06 6TLs. Never a previous issue. Battery voltage looks good. Takes charge etc. Try and start it and all gauges shut down. Turns out it was a bad cell in one of the batteries. All was great previously as far as starting etc. No hint of the failure coming. Just bring two good batteries with you and try it.

 

[rickf]

Ditto to the above post.

You could also try jumping it through the NATO connector on the pax side of the cab if you have either a friend with an mv or a couple of batteries. I'd disconnect the existing truck batteries first. If the alternator is good, once the truck is started you can limp home without any batteries.

NEVER run the vehicle with the batteries disconnected! You will be buying a voltage regulator, alternator and probably a lot of other electrical items. Without the batteries to absorb the voltage spikes you can easily put over a hundred volt spike into the system. At which point you will lose either the regulator and or the diodes in the alternator. Yes, I know people that have done it before too, so have I. I have also wiped out all of the above items so I have first hand experience. Sometimes your the windshield and sometimes you are the bug. Do you feel lucky?

Rick