SCRIPAL Posted July 7, 2015 Share Posted July 7, 2015 Can anyone tell me what this part is and it's function? It is on the firewall just above the power brake booster/mastercylinder. This is a 1989 Dolphin 6 cyl, however, it is a replacement engine. I am still having a hard time cranking the engine after it is warm. On a cold start, it fires right up. I have checked the ground cable and it showed that it is properly grounded. I also replaced both battery cable terminals with brass ones .When it fails to start, there is a clicking noise which seems to be coming from under the dash, passenger side. After several tries of turning the key, it will finally start???? Any thoughs appreciated! Thanks Quote Link to comment Share on other sites More sharing options...
Maineah Posted July 7, 2015 Share Posted July 7, 2015 It is your battery isolator. Quote Link to comment Share on other sites More sharing options...
SCRIPAL Posted July 7, 2015 Author Share Posted July 7, 2015 Does it have anything to do with cranking the engine? Quote Link to comment Share on other sites More sharing options...
jjrbus Posted July 7, 2015 Share Posted July 7, 2015 It is a solenoid, fancy electrical term for switch. When the vehicle is running power is sent to the solenoid by the small red wire and turns the switch on. The large black wire on the left terminates at the battery and the large black wire on the right terminate inside your RV at the electrical panel. These wires are easy to follow if you wish. When your unit is running and producing 12V the switch is on and allows the alternator to supply power to the RV. When your motor is turned off there is no 12 volt applied to the solenoid and it is turned off. This isolates the truck battery from the house battery else you would drain the truck battery. No it does nothing to start the truck engine and should be normally off when trying to start motor. HTH Jim Quote Link to comment Share on other sites More sharing options...
Maineah Posted July 7, 2015 Share Posted July 7, 2015 It does look like an old Ford starter solenoid but it's not. When you turn your key on you will probably hear a good "clunk" from it but that is normal. Quote Link to comment Share on other sites More sharing options...
Derek up North Posted July 7, 2015 Share Posted July 7, 2015 I'd add a shiny new ground from the engine to the chassis (or directly to the battery). Available, generally, pre-made in various lengths at your local auto supply store. Quote Link to comment Share on other sites More sharing options...
SCRIPAL Posted July 7, 2015 Author Share Posted July 7, 2015 Derek, I am not very mechanically inclined. When you say new ground from the engine to the chasis, just exactly where is it located on the vehicle? Is this ground you are identifying in addition to the negative ground on the battery? Thanks Quote Link to comment Share on other sites More sharing options...
Derek up North Posted July 7, 2015 Share Posted July 7, 2015 From a convenient bolt on the engine block to a convenient bolt on the chassis or directly to the negative (ground) terminal on your battery. Yes, this in addition to the ground cable from your battery to the chassis. Quote Link to comment Share on other sites More sharing options...
SCRIPAL Posted July 7, 2015 Author Share Posted July 7, 2015 I just got out from under the engine. I traced the negative side cable on the battery. It is bolted to the chasis and the bolt holding it down is a 9/16. Just before getting to the bolt, i saw the insulation has a gash in it exposing the copper wire inside. It does not appear that the wire is burnt. Is there a chance this could be causing the issue? Quote Link to comment Share on other sites More sharing options...
Vanman Posted July 7, 2015 Share Posted July 7, 2015 I think the loud click you hear is from the starter. The starter solonid engages the bendix clutch and then the starter motor contacts which suplies electricity to the starter motor. Next time it does this make sure it's in park and the hand brake applied and crawl under the pass side of the motor find the starter, bring a long wrench or a short stick. The idea is to have someone turn the key to the start position and hold it there if it doesn't start. You will be able to tell for shure now that the starter is making the click, next hit the starter with the tool and I bet it cranks rite up. Ours did this to us for the first time on a hot day after pulling over to the side of the road. I had the starter replaced with a "re-manufactured" 2 1/2 years ago along with a lot of other work, last time down the freeway and back in hot weather after a gas stop it just did the same thing. I had to crawl under it and wack the starter with a 12" cresent wrench while Mary turned the key, started right up and has started up rite away since. I do have a replacement starter now but haven't gotten it installed yet. Seems there is a heat related issue with the Toyota starters when they start to go away, I haven't seen that with the other starters I've replaced, they begin to just randomly start to fail, even on cold start-up. Quote Link to comment Share on other sites More sharing options...
Vanman Posted July 8, 2015 Share Posted July 8, 2015 I forgot to mention, on ours there are 2 black wires on the battery, one goes to the motor and the other to a bolt on the pass side engine bay. Since it's a ground if the insulation is bad and the wire is ok just tape it. Quote Link to comment Share on other sites More sharing options...
davidtan Posted July 8, 2015 Share Posted July 8, 2015 best way to test is to by-pass the solenoid and just unbolt the lines and touch the SOURCE to the FEED. If the engines turns , then the solenoid is bad. if it doesn't, then the starter is bad. Good luck Quote Link to comment Share on other sites More sharing options...
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