| Author | Message | ||
| Jim Wilkerson (Wagwar)
Registered Member Username: Wagwar Post Number: 176 Registered: 12-2009 Posted From: 74.94.161.193 Rating: N/A |
The discharge TT on my MC9 stays on. What's wierd is that if I air the bus up from my shop it goes off at 100psi, but if I let the bus air itself up it stays on. My Low Air TT also goes 'off' at 75psi, but stays on very dimly. I'm thinking the Penn Air switch, but anyone else have a suggestion? Thanks! | ||
| Dal Farnworth (Dallas)
Registered Member Username: Dallas Post Number: 738 Registered: 7-2004 Posted From: 98.20.57.197  Rating: N/A |
Rule #1..... Check the grounds. By that I mean run a temporary dedicated ground from the battery to the sender and the light. Rule #2..... clean out the air system. When was the last time you replaced/rebuilt the Air Drier? How often have you drained the air tanks? If you have drained the air tanks, was there oil present? Good Luck. Glad I don't have those problems. | ||
| Brian Evans (Bevans6)
Registered Member Username: Bevans6 Post Number: 85 Registered: 5-2009 Posted From: 67.71.36.165 Rating: N/A |
It could also be the discharge blower relay. Check to see if both discharge lights are doing the same thing, they are in parallel. Brian | ||
| Brian Evans (Bevans6)
Registered Member Username: Bevans6 Post Number: 86 Registered: 5-2009 Posted From: 67.71.36.165 Rating: N/A |
What makes me thing it might be the relay is that it is what actually turns the lights on and off. The control for that relay is from the RI terminal on the alternator (12v signal) to ground via the low air switch. So the whole thing is involved. That relay also turns the heat and AC blowers on. | ||
| George M. Todd (George_todd)
Registered Member Username: George_todd Post Number: 1293 Registered: 8-2006 Posted From: 99.48.215.44 Rating: N/A |
Brian, First off, can you read your alternator's output voltage? Should be about 27 volts. If 25 or lower, the light is on for good reason! Auxiliary air pressure is used for belt tensioning, and the no charge light, and the alternator field, are held out on my bus until the low air alarms go off, so the alternator will not slide the belt. The blower relay is held out with no charge, so the A/C compressor won't load either until air pressure is up. Does the bus air up and stand up? If not, the whole problem is the protection valve. Remember its a fiberglass dash, so if the ground wire to the metal part of the frame isn't good, current from everything else on the dash will try to get to ground thru anything it can. G | ||
| Jim Wilkerson (Wagwar)
Registered Member Username: Wagwar Post Number: 177 Registered: 12-2009 Posted From: 70.240.146.163 Rating: N/A |
I removed and bench tested the air switch, It seems to be OK. So I re-assembled, cleaned all the connections and now it all works great. No more dim Lo Air TT and the Not Gen TT goes off as it is supposed to. Thanks for all of your help! Just had awnings installed all the way around the bus at Consignment RV in Carthage MO. This is a great RV shop, careful, competent and reasonbly priced. I highly recommend this business. We got 5 awnings across the street at Colaw's RV Salvage and installed for a fraction of new cost. Check out the blog at: www.mightybus.wordpress.com |